Not to mention that pretty much all unions have very strong pro-seniority rules. I've not heard that about the UK's second largest union, Unite. I know people

Not to mention that pretty much all unions have very strong pro-seniority rules. I've not heard that about the UK's second largest union, Unite. I know people who work are part of that union (the people I'm thinking of work for BAE) and when they've talked about promotions and so on, they've never mentioned any kind of union-driven pro-seniority rule, and there is certainly no different vacation allowance for union members.