Firstly, people don't walk around with wet hair, so whilst it's a useful indicator of miniturisation, it doesn't mean you go placing a ton of grafts there.
Secondly, if this patient has aggressive diffuse hair loss, surely that is a reason to be MORE conservative with his donor.
Thirdly, transplanting in to native hair, especially miniturised native hair risks significant shock loss, so why take the risk??
It would be good to get other clinics opinions on this.