My previous hairdresser was great - he'd use hair clippers on the back of my very short pixie crop, but told me that the salon didn't really approve.
He then left, and my other hairdresser from the same salon refuses to use hair clippers to cut the back short enough. I really want my hair to be very short at the back, therefore I want her to use hair clippers 
!
I might try one more time, then vote with my feet.