I’ve run late for one hour bookings a few times over the years. In each case I called and said I will be there and will pay the full price but only stay to the end of the hour I booked.

For example, when I was 20 minutes late, I paid for the hour and she stopped the session 40 minutes later because she had other bookings.

Fair is fair. You take a worker’s time and it’s up to you to ensure you use it or lose it.

This works well when you’re a regular and they know and trust you.