Non union employees get the benefits of the unions collective bargaining, but don't have to pay dues.
The only thing taken out of my check other than taxes and such, is my $5 a week donation to United Way, and I decided to donate that.
Maybe your union stewards are a bit more aggressive than ours, or maybe it works differently in different states, but so far I haven't been pressured into joining the union at all.
In all honesty, getting insurance for part time work is great, and the 4 hour workout every night has helped me lose 30 pounds. It isn't a bad job at all in my opinion.