The idea behind the sign name for hearing is that the person is connected the the deaf community in some way. A friend, co-worker, job etc.
If you don't know them that well, then you obviously aren't friends with them, and they do not have other deaf friends, then they don't get a sign name.
If they give themselves a sign name, and then some deaf person asks them where they got it from, then they will be embarrassed when they admit they gave it to themself.
