I agree that a professional charging hundreds of dollars an hour should not expect to be tipped. But, it is a more intimate service than white collar professionals like accountants provide. While not the norm or expected, from what I experienced, gifts are not inappropriate. If you took your female accountant a box of chocolate or bottle of wine, that would probably wouldn't sit well. But, someone you are going to get naked in front of and exchange a deep emotional exchange...it isn't out of line.
