are some folk going to start getting over sensitive & hysterical about anyone videoing sessions ?

I know quite a few adults who would not be happy about their sessions being videoed, which is nothing to do with whether children are there.

I think it is at least bad manners to video a session without asking permission first.

Stepping over that red herring, I have been at several singarounds and mixed sessions where youngsters have sung or played, and they have been welcomed with delight.
The festivals I go to are generally very family-friendly; how about trying Warwick for example, Ben? 24th-27th July this year. My children have been attending with me since they were little, and now bring friends and spouses :)