Generally, the friends who will ask to drive your Z are exactly the ones that you should not allow to drive it.
If you don't want them to drive it, then you must
.
I'm an old guy and a stay-off-my-lawn type. I have had this Z 2.5 years. I let my son drive it once when it was new and in his HS parking lot on a weekend. I figured that would help satisfy his curiosity. My wife has not driven it yet. She has only brought up the subject in a joking manner, but if she asked seriously, I would let her. I am sure she knows what my reaction would be if something happened to my Z while she was driving it or soon afterward. She's a pretty bright woman.