Welcome to the forum! (You should put a link to your ad in your signature, btw).
As a client I would never book a weekend unless I had several 1 or 2 hour meetings before.
I also assume you wouldn’t accept a booking that long without knowing it is going to be a good weekend?
If you don’t know the client and don’t trust him, you realise you could end up in a nightmare situation where the chemistry is terrible for a whole 2 days and 2 nights?
So the question of a flaky client is irrelevant, you would already know that this client is not a flake.
As a client if I pay for your flight, yes, you give me your full name, so I can book it for you. No I am not just sending you the money so you can book it yourself. But realistically, if I pay for your flight, it is because we know each other well enough from previous meets. I don’t think I would fly someone I have never met.