Really it boils down to two kinds of profit motives.
First of all, yes, there is the monetary, but it may not be direct monetary. There's a simplistic one, where they have some kind of cash or money or a tradeable something, such as gold or whatever, and they pay for passage. That's very overt and above board.
The second issue that causes a lot of people a lot of concern is the fact that they put themselves in what amounts to indentured slavery when they get here in order to pay off the transit. For example, if they come from an area where English isn't a language that shows up on the language radar of the region, then in Canada they pretty much have to go to that ethnic community. This means that automatically, even if the Canadian government has intervened at some point in time, it puts them back on the radar to be tracked by the smugglers and told, “You have a debt to pay; you have to work it off.”
This amounts to years, potentially, of.... We've heard reports of $50,000 in transit fees that they would have to work off over years. If they refused or they didn't pay, there would either be a threat to them personally here in Canada or there would be a threat to family members remaining in their country of origin.
I think that's a big part of the challenge. I would say that the majority of them don't have the cash, and the majority of them, in my opinion, come into some form of “working it off”, if I can word it that way.