Some thoughts on confirming a date...
If I were an indy, I would first ask someone to contact me via email, describing what they expect from the encounter and telling me about themselves.
After the initial screening email, provide him with a number where he can reach you and set up an appropriate time to chat. An independent SP should always chat with the client prior to the date to a get a 'feel' for the guy (Anik even meets them prior to the encounter). Admittedly, this isn't perfect but you should still do it.
Do not ask him to provide you with a number right away, only after the second confirmation email. I do not deal with SPs who do not pick up the phone because of my blocked number. I never give my last name to anyone - ever - it's none of their business.
Then, as the day of the encounter approaches, ask them to email you a day in advance to confirm and to call you at the number in case of a last minute emergency, which can happen. Make sure you tell them that if you do not receive the confirmation email the prior day, the date is cancelled. This is where you can ask for a number in case an emergency arises.
By doing this, you put the responsibility in the client's hands to take some easy steps to confirm the date.
GG
P.S. Never, ever, ask for a deposit...you'll get laughed at.