Im sure the Custom officials did notice an influx of Organized Crime members, but what are they going to do about it. There are protocols and there are standards when it comes to who can enter either Canada and the United States, and if those people don't come into conflict with them then they are free to enter and roam for as long as their visitor visa allows.
If you're wondering why the paper wouldn't name names, well there are many reasons for that. Most likely though is that their source didn't want to divulge such information as it could very easily harm certain operations/investigations or even lead to a lawsuit/complaint.
It should also be noted not every gangster has a criminal record, its innocent until proven guilty remember. You may know someone is a gangster, but if you don't have it on paper, as proof, then you can't print it. Nor take his picture. But a cop who know's what the word on the street is can tell you hes connected and you can take his word for it. Thus they are written as Crime figures as opposed to providing identities.

Fact of the matter is you aren't going to get any explanations, not any time soon at least. Laws and sentences in this country are lax, so flipping a man in the know is about as likely as hearing Carmela apologize.
The Toronto Sun does not, nor any Canadian media outlet, have the resources to attempt to follow Vito Rizzuto around constantly btw. There is far more money in getting pictures of Lindsay Lohan leaving a porto-potty than watching Vito Rizzuto try to get his golf swing back.