Well, once again, I have to say my experiences have been pretty positive overall.
First let me say that working as a musician in Staten Island NY was probably not the same as working in some other places ... We were pretty isolated - the bridge from Brooklyn to SI had not been built yet - and access to SI was through 3 bridges to New Jersey and the SI and Brooklyn ferries ...
We had our own union delegate - who happened to know my father pretty well ... As a band we never gave him any trouble - except for a couple of occasions when we didn't have the right minimum number of musicians on the gig, and he really liked our band ... he even hired us for his daughter's wedding ... He also would hire us to open for an annual festival he helped run, and on occasion gave us a union paid gig ... He used to run concerts in the park during the summer and had a sound truck fully wired with mixers, mics, amps, and speaker systems, which he let us use a few times that we had big outdoor gigs ...
One year we were hired by a catering hall for a NYE gig ... we were the 'second' band and so we did not have to have the minimum number of guys for the room as long as the 'first' band did ... we played the gig and at the end of the four hours the owner of the hall sent the other band home and told us to continue playing ... we explained that we didn't have the right minimum, and the owner says "don't worry, everything's legit" , so we played for another 2 hours ... next day I get a call at 8AM, from the delegate asking "Tony, what happened last night?" ... I told him, and he said he would get back to me ... I never heard anything else ... I guess the owner was higher up the mob chain than the delegate ...
I believe it was the mid to late 70's when a band leader named Bob Chevy - who was the 'house band' for many NY catering halls, brought a suit against the union regarding the minimum number of musicians in a room ... he won the case and the court also said the union could not prevent non-union musicians from working ... that started the loss of union power relative to those of us who played primarily 'one-nighters' ...

The poster is from the festival circa 1978