at the big FBOs sometimes unless you're leaving right away you can't
get them to do it at a time you can be there to watch.

I was at Signature in BAL recently. I was staying a couple of days
and left an order to top off. The person at the desk asked when I
wanted that done, and I replied, "Any time before Tuesday morning
would be fine". She volunteered that today was Sunday and they give a
$0.50/gal discount on weekends, would I mind if they did it today? I
wish all decisions in aviation were that easy!