Oh man, your constant phrase of a well known tipper is alarming. Personally a customer generally tips well after a wonderful service. If the service is meh, then expect the tip to be lower.
I just think it is hilarious when people say the standard tip is 40 or 60. Sometimes a MPA would say a hj usually costs 40 or 60. I just smiled (because it is a stupid thing for her to say. It is not the first time.)
If a client is too cheap or took off without paying any tip, well they are a few and far between. it doesn't mean many of the hobbyists are like them. So I dont think it is wise for anyone to use that as an excuse to gather more tips from the customers. If so, it is all BS advertising.
To sum it up , NOOOO the standard tip is whatever you think it is appropriate. Entitlement is a dangerous thing.
PS. This is why I like Michelle. She 's good at what she does and doesn't bring up her tip expectation. Maybe she thinks about it but she keeps it to herself.