I think the OP is arguing that there should be a procedure in place, so you're not improvising, or making arbitrary rules that aren't fairly applied.
If nobody saw it happen and nobody knows either party well, I would say, record it and move on. If you have multiple reports, have a planned way to escalate, involving friendly warnings, going all the way up to removing the person and/or banning them.
Where it gets really bad - and I think everyone has seen this situation before - is when the guy is some sort of alpha geek, and may even be the kind of person that draws attendees. Everyone is inclined to bend the rules. I think that's why a standard procedure would be important.
If nobody saw it happen and nobody knows either party well, I would say, record it and move on. If you have multiple reports, have a planned way to escalate, involving friendly warnings, going all the way up to removing the person and/or banning them.
Where it gets really bad - and I think everyone has seen this situation before - is when the guy is some sort of alpha geek, and may even be the kind of person that draws attendees. Everyone is inclined to bend the rules. I think that's why a standard procedure would be important.