Always want to be respectful of a ladies time and not cancel, but late evening client dinners can often make advanced scheduling a challenge.  Would appreciate your thoughts.

That way I can freshly showered and just hold off on the makeup and such until I get the OK.  ☺  Also, gives me an opportunity to get the reference process handled.  

This is why I don't do many late evening appointments..... they do tend to be less consistent with time (both arriving, and overstaying), for those types of reasons.  

Last minute late nights never work for me unless they are arranged ahead of time for screening etc. Cancelling is the worst. It ruins my schedule and leaves a bad impression.

This way I can handle screening in advance, I have done a " tentative agreement" before and it works just fine because I can at least plan. I will usually confirm the day of.

My biz model.
xo

when I can't be completely sure of what time I'll be able to leave the office but am trying to accommodate playtime. I'd rather someone let me know their situation and we can leave it flexible than a last minute call or cancel. Last minute never ever works for me and canceling is a slap in the face/wallet.

Just so you know, I don't work late nights, or outcall with less than 1 or 2 days notice, so this is just my thoughts. (Family obligations make anything after 8pm very dificult without enough notice)
However...  it would be reasonable to accept an offer like this if the gentleman had already been verified, and I was already warned of the possibility of a later than expected meeting, within a limited time range. If the meeting ended outside of the time range we agreed on, he would already know I would not be there without additional compensation for time waiting. Say the dinner was expected to end somewhere between 6-8pm, and we would meet soon afterwards, I could live with that. But if it did not end until 10-11pm? That makes for a very long evening when I have so many other things I could have been doing, while 'on call' since 6pm.
This is why I rarely work past 8pm, but I will tell you that up front,

I am low volume so it works for me.  If it doesn't work out at least I am not all hookafied  banking on a good time

I had a gentleman who had booked an overnight with me and at the last minute he had to cancel because his Mother went into the hospital. By the sound of his voice I did not doubt a word he said. He also ask if he could send me a $500 cancellation fee which did floor me.  

Wow... That's a super cool guy!
Canceling with that kind of style would give him VIP status, and says tons about you as well!