I try to avoid working with friends. I had friends commission me, and once the friendship went sour, it became less of a business transaction and more of a hurt feelings thing. (So I refunded them. Of course I didn't want them to be out their money! )

Too many feelings, etc that makes stuff awkward.

If you want to have people abide by your ToS entirely (which is something I didn't do regarding the prior mentioned situation..) then it might be okay.