I've had clients that are cops, lawyers, judges and politicians. They are humans too.
I think the OP needs to understand a couple of major things. Never discuss specifics - it is time and companionship only. Never pick up someone who is working on the street (I know there are those that do, but the risk in my opinion is too big). Always make sure she is of age - any doubt, walk away. In Vancouver, she must be at least 19 years old. So, the girls advertising as 18 are potential problems, as they are more then likely to be even younger then that. Not always, but the Vancouver laws indicate they must be 19. Other parts of Canada allow 18 - so just be cautious.
There isn't a cop in this land that could ever MAKE me do something. So, no, they could not hire me to trick you. Ain't going to happen. However, there are stings in areas. They are going after under aged and those being forced/controlled by others. working on the streets. They are complaint driven. I work in this industry of my own free will. There is not anyone who can stop me from what I choose to do. Remember, it is legal for me to sell my services, however, it is illegal for you to purchase them. This is why I never specify what my services are. You are hiring me for a period of time - what we do together in that time is between you and I.
If someone is trying to get you to spell out what you want - be cautious. Don't use acronyms or street terms, thinking you are being smart. Just say you would like to see her for an hour (or whatever time you wish), and what is her rate for that time?
Have fun. xo