Yes.
There are two questions. One is whether non-union construction workers can live up to the same standards and comply with the same labour conditions, etc. as unionized workers. Absolutely. Law-abiding contractors do so. No matter what their union affiliation is, law-abiding contractors obey the law.
As far as temporary foreign workers go, if that individual did violate the terms and conditions of the LMO, then absolutely, throw the full weight of the law against them. That's absolutely a situation that should not continue.
Our industry, quite frankly, has used the temporary foreign worker program only because the permanent entry program up until recently didn't work for us at all. We've streamed most of those workers into becoming permanent residents and permanent parts of our workforce; and indeed, we would never want to have a situation in which we were paying them any less than what we were paying Canadian citizens or permanent residents.