Can someone get their license taken away if they go to a park after dark, went off roading, turfed some grass?

For the record pleading Not Guilty is NEVER Contempt of Court. You could be filmed doing it and the police could have a taped confession and it is STILL not contempt of court to say you aren't guilty. In the US we are given the right to trial if we want it. Now if you were video taped doing it and signed a confession that it was you(after being read your rights and everything) then there isn't much point to pleading not guilty, but it STILL would be the option if you wanted to take it.