This was mentioned months back. Supposedly a lot of the youngsters are the culprits. It's unfortunate but that's football changing room like banter.
Yeah it happens everywhere really, but to do it in front of Emery or so he can hear/see is really disrespectful. You don't have to like him, but they should act professionally when they are at the training ground.. The fact that it's the youngsters makes this even more disappointing for me.