Everyone else is shooting you down..but...

People beneath your PK range should not be able to grab a disarmed holy weapon. An IC reason would be that the unholy weapon is too powerful (with enough charges) for a lowly adventure to touch. OOC, though, I really hate when people gather around a fight, mouths watering, waiting to pick up a few scraps. Its pathetic and annoying.

Perhaps the real issue here is looting disarmed weapons though. I find it a little absurd that someone would be able to grab a weapon that is at the feet of two people fighting to the death. It seems more realistic that this person would chance being trampled or get a "gods protect" message. (Perhaps a new thief skill.)

In the case of unholy weapons, it is a moot point. After playing 3 hero rank APs...with a few hundred hours at hero, I can honestly say that disarming was never a problem with that Iron Grip thang.(See Zulghinlour's post.)