That was my thoughts exactly and I guess it works most of the time but it went wrong for me when she disappeared with the money when I went to breakfast.
As far as I was concerned I had kept my side of the deal by paying travel expenses and the 3 day fee upfront. No support from the agency (only concern was whether Anna had got the money off me before she left) and was left with hotel and flight bills not to say a ruined holiday.
That sucks! A bit like a UK overnight that didn't work out, but more expensive and more disappointing!
I think the cautious (but probably unfeasible route), would still be to try before you (fully) buy. I have done long UK bookings without having met the escort first and based on about half a dozen, the best long meetings have been with girls I have seen previously.
As you say, it sounds like SB work most of the time, but there's a chance it will not. Risky...