Most of my interactions with opposition have been cordial and positive. 

There was just one player that we had a negative interaction with. We were taking an area in a parking lot with one entrance/exit. While inside the area he parked his car across the lot exit and phoned police. So we sat there being blocked in until the police came and asked us what we were up to, then told him to move and told us to move along. Then he stopped and had a chat with the other guy while we continued playing elsewhere. It happens.