Do you tell people in advance about your child's issues? Especially if they're issues that aren't immediately noticeable or could be misconstrued as 'bad' behaviour/parenting?

So, I have done two workshops in the past week, both for parents....both said chn are welcome but participants can obviously concentrate better if chn aren't around. Unfortunately, DS has had no choice but to come with me....

....now, he's not a bad kid, but his one of his sensory issues means that he often needs to 'fill a space' with his own noise, especially if it's an unfamiliar place, situation or people. If there's already noise, he has to be louder. We generally get a running commentary of whatever he's up to at home, or humming, self talk or singing. We're used to it. But in a workshop it'd be darn annoying for most people.

Today he totally freaked out, almost threw up, came over all hot and clammy, then proceeded to stand semi-comatose for a good 15 minutes, just staring at a notice board of photos....he had worked himself into such a state he eventually fell asleep for the rest of the workshop. This is totally uncharacteristic of him and I assumed he was having a relapse of the bug he had on the weekend. He can sometimes get upset if he sees something he doesn't like (realistic animal paintings or toys etc hanging from a ceiling will make him not go in a room, for example). It wasn't until we were leaving that I saw one of the photos was a painted preg belly with a kind of monster type face on it -big white teeth and green eyes etc. That was what had freaked him out!

The two presenters today both commented on how DS' freak-out had freaked them out, and several people at the first workshop commented on DS' constant talking and moving about. Not in a nasty way, just in a,'well, you can't miss him, can you?!' or a 'he's definitely a boy!' way.

Should I have told the presenters (the whole course?) that DS has some sensory issues and is likely to verbalise the whole time, or perhaps even freak out? I don't feel I need to justify his behaviour, or be told he's not welcome, and the vast majority of the time you'd never know there was anything different about him. But is it rude/inappropriate of me to not warn people in advance?