[SwedishExpat]

> Clearly it's not as simple or cheap as "zero cost"

It really is! To leave a union you just leave. You'll miss out on some perks like topping up your unemployment insurance though.

> Whether you benefit from something is irrelevant to whether it's "forced" or not.

You can get most of the perks without being a member, because membership is anonymous within companies and unions have argued that everyone receives the benefits due to this! So you can have most of the perks of a union without paying "taxes", but I think it's fair to chip into the pot.