If you find a deal you cannot believe, do not believe it. Virtually all established agencies or well reviewed indies are exceptionally unlikely to rip you off. Quality of the experience though depends on who you pick. Read the reviews.
We have a vice squad in Canada and they do raids on Massage Parlours and incalls. Mostly because of complaints from neighbours or the public. I did not research it, but I was told they try and do at least one raid a week. For the suppliers to talk about it would be bad for business. I know they do at least some because an aquaintance got charged as a found in. His lawyer told him talking about it was an incredibly stupid act. Our laws do not require you to be naked, to have been caught having sex, or much of anything. Being found in is a criminal offence.
Your concern should be that as a visitor they can easily assume you would run back to US. We do not have a bail bonds man system in Canada. Make certain you have accesss to a HUGE chunk of cash.
How risky is it? Assuming we have 200 places in GTA that might be raided, and assuming they are open 10 hours a day, and assuming 30 days in a month .... that is something like 50,000 hrs available. Assume they do 5 raids a month, you have 1 chance in 10,000 of being raided / hr you spend there. For a Canadian whose job does not require a police check, not bad odds. In your case, if the call to your employer to verify your employment status (for bail), to your wife (if you have one), the cost of returning to Toronto for the court date, spending time locked up until you can provide bail, legal fees, etc may make the outcall a less expensive idea.
Before the comments fly in, for locals once they are convinced you are local and employed they let you out without bail.
Good info here, but there's always more. In Canada we have a single Criminal Code that covers the entire country, the provinces just enforce the laws—they, or their towns and cities run the vice squads—the feds make, unlike you guys where the states make the criminal laws and enforce them. So there can be considerable difference across municipal boundaries about just what is done about the same criminal offence. But as to the offence itself, just one flavour.
There is no criminal law against anyone fucking for money, either receiving it or paying it. There are laws against running whorehouses (Google 'bawdyhouse'), being a possible customer in one (that'd be Loki's 'found-in') working in one, or pimping in general ('avails' is the archaic legal term) and there are also criminal laws against publicly doing sex-deals that make streetwalking or being a customer criminal. But if she shows up at your place you are in no criminal law danger offering money or handing it over to get sex.
Different if it's not your place, because it might meet the definition of a bawdyhouse, and that's where the ten-tonne weight crashes down. Now as to MPs' if the local folks are reasonably comfy with clean staff in clean places offering just a rub'n'tug that gets inspected and passes regularly, then they won't go through the hassle of collecting evidence and prosecuting it as a bawdyhouse. But they could, and in Vaughan just north of TO, they very much do. If she advertises and makes and appointment at her place, you could be stepping into danger there; if you're just one of many customers, her place qualifies as a bawdyhouse. But again, they'd have to get the evidence, not of just one, but of repeated sex-for money deals.
So briefly: Outcalls are very safe. You or she could in fact call the cops if the other party didn't behave. The agency that sets it up may be pimping, but thet's nothing either of you need worry about. Incalls can be safe, but are illegal, pretty much without a defence, unless you were the pizza guy, could produce the phone order and still had your pants on with only the pizza hot, as you have to be found-in
without lawful excuse, but that is all the cops need. But they still must prove the place offered and delivered sex for cash repeatedly, 'cause if they can't, then you weren't found-in any place that matters.
Two sidelights of interest: One judge did toss out a bawdyhouse charge against an MP. His take was that nobody actually bought or sold a handjob, even though it had been proven one was delivered. Absent the cops evidence there was deal, he saw no reason to believe it wasn't just a spontaneous part of the overall nekkid fun which had been bought and paid for under the city license, and threw out the criminal charge. That was a lower court and hasn't been given wider authority by a higher court. No word on whether the spa kept its license, and that's as critical to what you get in one as the Criminal Code.
Second: There is a case before the Supreme Court, in which the feds are trying to overturn a lower appeal court's ruling that the current laws force sexworkers to ply their legal trade in dangerous ways contrary to their Charter rights, since effectively the only legal way is for her to take her own calls and go, with no backup, to the premises of strange men who might well assault them or worse. (Google 'Pickton pig-farm') That case has not been decided, but technically all those laws are now on a temporary basis.
The basic behaviour rule flows from the fact that prostitution is not illegal here; stay discreet, be polite, do only what you see the locals doing and you should be just fine.