I can only recall one time seeing someone being verbally combative. It was when I was spectating at the Lakefront Marathon in 2007. At about 2 miles, the course goes by a cross-street with a church on the corner. Apparently, there was some pre-mass preparation some people needed to get to the church for. Some guy got out of his car after waiting what couldn't have been more than 10 minutes and got hot headed with the police officer who was controlling traffic. He was yelling about his Constitutional right to practice his religion and how the government was taking away his Constitutional right and he was going to sue everyone he could think of. All I could think of was how this guy was making himself into the antithesis of what Christians say they stand for right in front of his church and fellow parishoners and, quite simply, making a fool of himself.
The police officer handled it very well. He said repeatedly the last runner would be through in a short amount of time and the vehicles would be able to cross immediately after the last runner passed (as was the case). Even in the face of someone getting increasingly combative and abusive, the officer simply held his ground in a non-combative, respectful manner. Heck, I was tempted myself to go over and tell this guy off and I wasn't even the target of the verbal attacks.