Sometimes I ask them if they are a policeman, and if they say yes, I ask them if they'd like a compensated romp.
(Not policemen on duty! Only if they email me first.)
We obviously don't need to worry about being arrested which is what would make my brain explode in fear were I ever to try and work in the US. Adultwork.com is big here and gets a lot of traffic as well as having a lot of features, including ratings of both escorts and clients. Providing they haven't chosen to have their feedback hidden, you can have a really good nose through clients' feedback, the feedback they have given other escorts, which escorts they have been to see and what services they went for etc etc. The feedback can be a little sparse, or misleading, or just downright silly though so you have to pick and choose and try to build up a bit of a picture by reading 'tween the lines and all that.
Otherwise, I'm a bit embarrassed to say that I don't verify my clients one bit. I don't confirm their real names or where they work or where they do their weekly shop, usually (sometimes these things do get covered in casual conversation
), so I keep safe by making sure someone knows where I am when I'm working, and the contact details and name of who I'm with. Plus check-up texts after the appt.
I think we all weed out timewasters and nutters with our special antennae, over here.
I don't get many no-shows at all so at the end of the day, if someone doesn't turn up, I'm usually a bit relieved that I can then get back into my PJs and eat macaroni cheese and do some more reading or whatever. If you need to be more strict with TWs though, there are a few different methods SPs here use to weed them out!