I know 2 people with union jobs. Neither have weekends off! Neither do I, necessarily, I work when I want. Nobody has a right to tell me I can't.

Very good chance they are paid overtime on the weekends.
I too worked more weekends than anybody I knew but at time and one half for the first 8 hrs. and double time after 8 hrs. on saturday and
doubletime all day sunday I was well compensated In my situation the company needed you to work the union only set the pay rate, everybody was happy.