The crime is called 'operating a bawdyhouse', but think of it as running a brothel, a place where guys go to buy sex. If it's always a different place, then it ain't a bawdyhouse. The only crime the SPs commit is working in a brothel, so that's why going on outcalls is OK.
If a Court is going to convict anyone of running a brothel, or convict you of working in one ('being an inmate' is the name of that crime) they have to have evidence that sex was bought and sold there, not just once, but frequently. Very hard to collect that evidence. Especially since it is not legal for cops to wiretap or set up cameras in private places. Not unless a judge has looked at evidence of crime they already have and decided it's OK to get more in this way. If the cops couldn't find customers or girls willing to be witnesses, they'd have to send in their own guys to repeatedly buy sex, and have it provided. It's not the sort of thing they'd want to be cross-examoined about by your lawyer. Frankly, unless the neighbours are complaining, why would the cops even go to the trouble?
In the US the laws are very different and we've all seen and heard about prostitution stings on shows like Cops. But they work because in that state, it's a crime to offer sex for money, or to offer to buy it. In Canada, that's only illegal if you do it in a public place, and the police do use stings here to keep the lid on street prostitution. They'll use a policewoman who will bust a guy cruising, if he rolls down his window, and asks, "How much?", or a cop in his own car who sees what offers he gets from the girls. "Communicating for the purpose of prostitution' is an equal-opportunity crime. But in a private place, like your room, it's perfectly OK.
There is just no effective way to set up a fake bawdyhouse (and if it was the cops running the whorehouse, they'd be the criminals) to trap real customers, or to send fake customers into a real one unless you actually do the bought sex that makes it a crime. Without that sex, there is no crime. That's why smart police forces are doing what they should always do: focussing on abuses of the those in the trade, and assuring them that their complaints of pimping, underage sex, trafficking and violence will be acted on just as any other law-abiding citizen's complaint would be.