I dont want to get into detail here but...

My worst experience was trying to deal with a disgruntled team member, who was kicked off the team(definately for the right reasons). He took pictures of our robot in development and posted it on a website that was advertized.

Personally, I could really care less, since it was about 3 weeks into the season. But our team made it a really big deal and in my opinion, it gave more power to the abuser.

Eventually everything died down, we got the site removed and (somewhat) reconciled with the member, although he is still banned from the team. We went to Canada and we won, so everything turned out ok in the end.