A kick feature could be easily abused, too.
I think Blacklisting people for healing while using DF is stupid. If you want to "meta" with DF, do it in TA games. DF users drag the rest of the party down the overwhelming majority of the time in normal play because everyone has to tiptoe around them. If anything, I'd rather blacklist THEM for being obnoxious at everyone else's expense.
The amount of time you'll spend perfecting the art of DFing without constantly dying will far exceed any amount of time you'll ever save using it. Don't blacklist people for trying to stay alive and not wanting to spend 40k on consumables every run.