Just because you are salaried and "professional" does not mean you collectively do not have extreme clout.
Whatever the hot issues are - say hours worked in a 7 day period - and the desire is to place limits (say 4 twelve hour days amd 1 eight hour day) having a union attitude means your bargained (agreed upon) rules are enforceable. And you carry a right to not work outside your agreed upon scope.
The attitide comes in when you stop work after the last day. It's your right.
People in unions (i am one) are the beneficiaries of years of compromise and abuse But it's fragile.
All the union is is a sturdy frame which everyone stands on. Its sure footed. Otherwise workers - even professionals- have no true security, no true predictable work conditions.
Iz is very unfortunate that union has become such a negative word. If a handful of people got together and simply stopped the management "abuse" i guarantee (!!!!) you you would be surprised how much power even engineer types can have