This type of situation doesn't happen very often, but it does happen from time to time. They would threaten a vote but they wouldn't go with it or be advised not to. If they did however, first, I would tell the ones behind it, the people saying "We need a Heavy Rush and we will ban you if you are not one!" I would tell them that not becoming a certain class is not a banable offense, while voteban abuse/spam is. Some people on the server would know that banning people for not playing a class is stupid, and would vote no when the vote comes up. I would vote no as well to counteract it. If enough no's pop up, then it will be counteracted. If I know beforehand that they would activate a vote, I would attempt to use a vote cancel. ex. Voting to Slay an already dead person or myself in order make the /votemenu be on cool-down.
In the very cases, where the person DID get banned, I would defend his case if he tried to appeal to the Skial Forums.