Patrick, some of these ideas were also discussed in this previous thread - Ang

https://www.racingrulesofsailing.org/posts/272-recalls-and-penalaties

Technically, yes - the RC should fly the X-ray flag at the "proper" start since the boat is on the course side of the starting line.  However, the risk of confusing the other competitors in that start is high, so even if the RC was aware that the boat started with the wrong class, it may be best if they did not fly X-ray unless there was another OCS boat in that "proper" start.

The boat should be scored OCS.  Case 31 is the defense of the inevitable request for redress.

Matt, I’m also thinking there is a rationale considering what the purpose of the X + sound is, and that is to notify a boat such that they can correct their error, and following the removal of X when the correction is made. The intend in the design is reactive  communication based upon the actions of a close-by boat. 

A boat that is 3-5 mins down the course will not benefit from the visual X and sound signal and as you say, will only serve to confuse other competitors. One can imagine one such confused competitor returning to the course side only to see X still flying and thinking “What-the-heck” as seconds tick by. 

On the other hand, if the RC is calling #’s over VHF, then the X+sound might be less disruptive as in my experience, we wait to hear our number before heading back. 

Can you elaborate on the PC’s Case 31 defense in a redress?

Ang

Seconding the comments that signalling OCS would be confusing to boats in the vicinity of the start line and of little value to the premature boat.

Perhaps a score of DNS would be appropriate as the boat did not comply with definition of "start".

Rob, check the "definition" of OCS in A11 - "OCS  - Did not start; on the course side of the starting line at her starting signal and failed to start, or broke rule 30.1."

I might argue that you don’t fly X-Ray and simply score the boat DNS (assuming they don’t come back and start). Yes, technically the boat is OCS, however she’s nowhere near the starting line and as such could simply be scored as not having started.

To be fair, this is simply off the cuff, haven’t had a chance to look through cases/appeals.

Edit: I see Rob basically said the same thing before I got a chance to submit

Case 31 concludes that the omission of a sound signal required by RRS 29.1 was "clearly improper," thus entitling the OCS boat to redress. But in the Case 31 scenario the OCS boat was in a position to hear the sound signal, had it been made, and presumably would have returned and started properly but for the omission by the RC.

I could argue that in this scenario, where the OCS boat is some distance down the course, she would not be in a position to see the visual signal or hear the sound signal, or if she saw/heard them might not understand that they applied to her. As these signals (in the absence of any VHF calls if allowed for in the SIs) would likely not have benefited the OCS boat and may have confused boats starting properly, I'd say that omitting the signals, while not in accordance with RRS 29.1, was not necessarily an improper action in this circumstance.

A related question occurs to me. If a boat starts with a previous class would it be proper for the RC to call her on VHF and inform her immediately, or should RC wait until her correct starting signal and then hail?

What about another competitor hailing the OCS boat to let her know she'd started with the wrong class?

The gist of Case 31 is that a boat is entitled to redress if they did not believe they were OCS and the RC failed to make the correct sound signal with the display of X-ray, thus depriving the boat of the opportunity to start properly.  On the other hand, if the boat believed (or knew) they were OCS, then the improper action of the RC was moot - the boat should return to start properly and by requesting redress, risk a rule 2 protest by the PC.

In this case, the boat starting with the other class may not have known they were OCS at the time they "started,"  but certainly knew when informed of their error.

In both cases of hailing in your instance, Tom - neither violates rule 41 since the outside assistance is unsolicited.  I (as RC) would be hesitant to hail since I might not be able to do it in all instances - violating the "consistency principle" that all RCs should aspire to - to treat all competitors equally and consistently, no matter the circumstance.  However, the "good guy" in me probably would, considering the level of the event, knowing that multiple, successive class starts are rarely part of a very high-level event. 

The real question is whether the boat that started early could claim redress if there was no recall signal at her proper start.  Rule 29 is mandatory; if a boat is OCS, "the race committee shall" display X and make a sound.  So if the race officer doesn't do that there is an improper action.  But this boat started some minutes, probably five, before she should have done and when she at last realised that she did so, she must also have realised that she was clearly OCS at the time of her proper start.  According to Case 31 if she applies for redress she is probably also breaking Rule 2.  I reckon the race officer would be absolutely right not to display X and signal.

I think I’m coming around on the question, IF (and only if) the RC is calling OCS sail numbers during this event over VHF, i think the RC should X+sound at the gun.  Here is my reasoning:

At the proper start, there are 3 possibilities ...

#1) No additional boats over
During the gap between starts, the RC has discussed this boat’s OCS status. Flag, sound and VHF are prepared. X+sound quickly made and sail number ID’d over VHF. I think that would have minimum impact if any on the racers starting properly. 

#2) Additional OCS boats at the start.  
X+sound at the start. The list is assembled and the boat-in-question’s number is added to the VHF list. No other boat is harmed or effected. I doubt this scenario would happen when starting penalties apply but if so, they would be applied. 

#3) General Recall
1st-sub + 2 sounds. The RC might make the point to name the class for which the general recall applies over VHF.  Typically the RC may do this in context of announcing if the class will restarted immediately or go to the back of the line. 

Ang

Read the SIs and know what fleet you are in.   Boat should be scored DNS because she did not sail/compete in her start sequence.

The Race Committees job is to do starts, log times...in the theoretical start, the boat in the wrong fleet didn't start over early so why would the RC display the over early flag...that would mess up everyone, and the race Committee, protest committee and the race chairman would receive unnecessary flack... the statistician sorts it out

Note that the guide for Sailing Instructions has changed 
from "a boat that {starts too late) shall be scored DNS"
to "a boat that does not start within X minutes after her start signal shall be scored OCS or DNS..."
This includes OCS boats and boats starting too late and removes the implication of such boat being a "starter."