As of right now, if you want to test that someone is member of a group, you need this person to be actually wearing the group. Which is fine when dealing with vendors or fidelity. However there are scenario where you want to be able to test if a person is a member of a group without them actually wearing it. For example, accessing something or security or special functionality.
In the same fashion as
llSameGroup(uid)
works, we should have a
llHasGroup(uid)
which would let you test if someone has the group even if not explicitly "wearing it".