They could possibly be denied membership by the United MEC, but don’t expect national to really care either way. Alpa National is the same group that made the pilots at Polar sign statements to end the strike of 2005 saying that there would be no retribution to any alpa pilot who crossed the line. Polar pilots were all locked out and couldn’t cross if they wanted to, but Atlas (some, not all) crews were brought onto the field from remote locations to fly Polar flights as a “charter”. Hard to believe, but it happened.