Whether the project is at the Ottawa airport or here, on Parliament Hill, if the general contractor has signed an agreement with one of the unions and was awarded the contract, the construction site is not accessible to me if I haven't signed an agreement with that union. I'm penalized because I'm not unionized.
As Terrance mentioned, you can choose to join a union, but you shouldn't be penalized for choosing not to. And that is my experience. I am being penalized because I chose not to go that route.