What relationship do you wish to cultivate?
In order to detach your contribution from their behavior, or in order to attach your contribution to their behavior?
My coarse understanding is that decades ago the gratuity was originally before service, so that one could establish the quality of service they were requesting.
This can be achieved by what you intend and practice.
xmunk@sh.itjust.works 5 weeks ago
Hourly, set it up on auto-pay.