For every vote it wins them, the proposed abuse of privilege will lose them three votes.

Anybody who doesn't think the idea of running the pirate bay out of parliament is awesome, hilarious and/or a gesture they want to make probably isn't voting for them anyways.

They're not going for mainstream votes, they're trying to amp up a small base -- extreme works.

Perhaps the three votes wouldn't be cast in their favour anyway?

I disagree; most of the people who would regard it as an abuse of privilege aren't planning to vote for them anyway.

The average PP voter will probably regard this as a use of privilege, not an abuse thereof.