If it is a matter of hygiene with ANYBODY - SP, friend, co-worker whatever, - it is a great favor to actually tell them that they have a problem. Might be slightly embarassing, but maybe they didn't know.
On the other hand a personality thing may lead to an angry response if they have a lack of emotional intelligence.
Tricky problem.
I saw an SP once who I had been a bit of a regular, then she left the country for a couple of years. I took a break myself from the hobby, and changed my phone number.
Then out of the blue she was back, so I booked her
When I went to see her she came down the hall of the Hotel to the back door to greet me which I thought was odd.
She looked at me and said, "Oh my God, it's you. I'm so glad its you"
Then she told me she had another client that never stopped trying to get her to do anal who had the same first name as me. She couldn't get rid of him. So I guess she had the same problem.