I have been using Wickr for years. It automatically deletes all messages after a set number of minutes (like 2 minutes). Also it blocks the phone from taking screenshot or save pictures, copy / paste words.
I am wondering why providers and hobbyists don't use such as apps to contact on the day they are scheduled to meetup.
Also, have anyone thought of accepting alternate methods of payment instead of cash? My friend told me that in their city, providers sell condoms or something else for the price of their session, and then whatever happens is between two adults. Not a bad idea it seems. No exchange of cash for sexual favors.