To be fair most aren't unreliable, I've had plenty of unanswered mails, I've turned up at a location for a booking only for the SP to stop responding to messages asking for the address, but 90% have been spot on. Decent research and switched on Spidey senses when replying to enquires is usually enough to prevent problems.
I messaged a girl in an area I'm travelling to tomorrow, decent pictures, all the services I wanted, some of the wording in the profile was a little strange and there were no reviews on here, so I mailed asking about the service advertised and asked her to confirm that she was British as her profile suggested, when I checked later it said "mail deleted" I didn't peruse it.