Maybe it's a different issue with the federal government. I'm not sure.
What I can say is that we have workplaces and employers who try to contract out large amounts of work. We have many collective agreements across this country at all levels, in provincial and federal sectors, with provisions that give workers support and that say certain work can't be contracted out. Sometimes it's tied to employment levels: As long as everybody is working, some work can be contracted out.
If I'm a tradesperson and you bring in an outside tradesperson, I'm going to start to wonder why the employer is doing that. Is it simply a need, that they need more tradespeople? If so, why aren't they hiring more tradespeople in the workplace? Those types of questions would definitely come up.