It's apparently only a criminal offence in football, still shouldn't happen and I doubt the kids would run on if the idiotic adults didn't run on first.
The age of running on for players tie ups is long gone. It's completely unacceptable for spectators to enter the field of play and they should be banned.
If you're really that weird that you feel you have some sort of personal connection to people that you've never met but just happen to play for the club you support so need to show your undying love for them, then hang around outside the players entrance for about ninety minutes after the game you gormclops.