That is a related but not necessarily the same issue.
Clearly we know that calling an sp from a cell phone that can be overheard in let us say Union Station is not wise.
The question however is if that conversation is intercepted (it does after all travel by radio wave) is it private as is a wired conversation or not, being rather like that call from Union Station even if you make the call from entirely private place. This by now is beating a dead horse, since my question merely is this a question that the SCC has directly answered.
You could pick up a ham radio and communicate for the purposes of prostitution and broadcast it to half the country, and it still wouldn't matter, because a radio wave is not a place. Similarly, and obviously more commonly, you can post ads for prostitutes in newspapers and in public online forums like terb or craigslist, and it's not illegal because neither a newspaper nor terb is a place, even though both are (somewhat) public.
It helps to remember that the purpose of the communications law is not to stamp out prostitution entirely, but rather, prevent it from interfering with people on the street, and other public places, who are going about their ordinary business. It's targeted at "red light" areas where prostitutes line the streets and flag every car that goes by. That's why the law references a "place".
