Mafia and unions have very close ties historically, not only in Leone's Once Upon a Time in America.
As for topic generally, unions are like communism (also close ideologically): they may look nice on the paper, but in real world, usually the worst possible solution.
I've only meet career-first scumbags in unions. Generally we in IT tend to stay away from politics and just do our job, which is exactly what unions are about. Plus, who is really trembling for his super-hard-to-get position? If I'll get fired/decide to leave, and I'll just pick from those recruiters spamming my inbox/linkedin periodically. Now if you didn't catch up with trends of last 20 years, you may need to worry a bit...
I've had friends beaten, others threatened. They've consistently threatened other friends with forced membership.
No thanks.