I've had overnight bookings with people I hadn't met prior to it. I guess I've been lucky because they've all worked out fine. I had one two hour extend to an overnight. We just stopped, ordered room service and he paid me the rest before we re-commenced. So they can work. Then again I'm a good actress and I could use the whole evening talking about the client. As long as I'm fed well,lol.
I had an overnight in Scotland a few years ago. Although the customer had seen a wg friend of mine when she toured Glasgow, I asked for ?100 deposit, the airfare to be paid, plus the hotel room, before I set foot outside the door. That was about ?300. My overnight at the time was ?600. That was no problem.
I disagree (it's rare that I do) with Ani-Mae. If he is serious, he'd have the money to hand to send to you. If he's done it before he'd understand your need for security. If he could afford it, I don't think ?50 is enough of a detterent.
But if you're leaning towards not doing it, then my opinion is moot anyway. And I also think he's a timewaster.