I've just got back from a Labrador social with my 18 month old male Labrador. He is well socialised and has the chemically implant. He's always been overenthusiastic and lies down for every dog he sees on a walk. Sometimes he barks if he doesn't get to meet them. So he is a bit reactive and we are working on this. He is only off lead by himself usually, except he goes to a very small doggy daycare once every 2 weeks and they say he's absolutely fine with the other dogs.
Anyway, we've just been to this Labrador social with around 10 other dogs. It's at a training centre and has a member of staff supervising. Our dog was mostly fine BUT got really overstimulated and was persistently barking at the same 3 female Labradors. Nothing the guy did would stop it and I was also trying. He was completely oblivious to the other dogs snapping and I had to keep putting him back on his lead several times. Out of these 3 female Labradors: one belonged to the person running the session (her season ended 2 weeks ago and she was tethered), the other also belonged to the same guy and seemed protective of the other one, and the third one I think knew the other two well and they stayed in their own small pack.
The guy running the session has suggested further training for our dog. Don't get me wrong, I know he can be reactive (excitable and frustrated) so we will work on this, but am I right in also thinking that his female lab just off heat shouldn't have been there?
He was also feeding treats to the dogs when the session is strictly "no food".