The problem is, if you give a girl a gift. No matter how small or large. You are showing her directly you are a soft touch. Most girls will not respond to being given a gift by thining "I need to up my game for this punter". You will infact get the opposite response and reaction. "this guy is a soft touch so I can just give him the bare minimum and he will leave happy".
The girl will claim its a "GFE booking" she is doing as a result, but really its the low effort taking the mick booking.
The best gift you can give a girl is the correct money, a rebooking afterwards, and a positive review for that booking on the forums. A bottle of wine, or a cake, or some chocolates don't do it.