Depends on you... the gun... and your level of trust of the other person.
If you are really worried about your "friend" committing a crime with your gun they borrowed... then you probably need to re-evaluate your friendship.
Ever see those gun reviews online? Most are borrowed from fans/friends or the manufacturer.
I suspect many claim the reason they do not allow others to borrow and take it out of their sight, is for "legal" reasons...
When in reality... its just simple personal attachment to their guns. Though they might not realize it.