Hey Horn Dog, here is some input from an SP if that's ok
You said "Maybe it's just me, but I would think most would want an hour visit most of the time. It seems like a very hefty request in my opinion, but maybe I am wrong...."
Hmm..not true for me. I'd say about 60% of my appointments are for 2 hour sessions, 35% are for one hour sessions, and the remaining 5% are more than 2 hours long.
Since I ask 600 for a two hour session, it goes to show that there are plenty of people out there with this kind of money. Otherwise, I'd be charging lower rates.
I'm surprised that this SP is able to require a 4 hour minimum, but just like in my case, she wouldn't ask for it if she couldn't get it.
My guess is that a lot of her clients are from out of town, and since she has such a long min appointment time, I bet some people will spring a little (a lot?) extra and have an overnight session.