But now you're exposing the huge problem. It goes from "everybody has to be able to cancel their account in the app" to having to be a contract lawyer steeped in the specifics of every business arrangement and know the law in a hundred different countries to be able to determine if you're allowed to cancel within the app.
Then the app reviewers would either have to be lawyers with plenty of time to make an accurate determination, or they'll be getting it wrong left and right. And it'll obviously be the second one. So now what does the dog kennel owner do, or the OP above, when the app reviewer rejects their excuse?