Clock watchers are the girls who try to push you out the door 10 to 15 minutes prior to time being over. Clock watchers tend to be the providers who either double book or book clients back to back. Most of the providers I've been with are hardly what you would call clock watchers. Most of the time if we are running up against our agreed on time, she will gently say time is about up. I've never been in a situation where I was trying to get an extra nut in. It has always been during pillow talk time where the gal drops the subtle hint.
Also in my experience, I've run across providers who really don't care about time. This is especially true if they are low volume and the rest of their day is clear. More than once, a lady has said I could stay as long as I wanted with the implication that no "second" donation was required. Now, those are truly the gems in this business. BTW, I've never accepted their offer to stay (but I might in the future).
Additionally, I only bring the original agreed upon donation. I do this for several reasons. First, I don't like running around with large amounts of cash. Second, I can avoid upsell situations. There are some unscrupulous providers out there that will promise one thing and then try to upsell it once in the room together. While it hasn't happened much or lately, I won't play that game.
Finally, I am entitled to a partial refund if I leave before our time is up
Actually have done it several times because the provider was not that good.