As far as I know there was no rule against dropping weapons on our server (whether it's done using the keybind or suiciding with the weapon).  I don't see anything wrong with it.  It's actually a required keybind in some TDM competition/pug rules.

Dropping weapons is more useful when teammates need weapons (and this seems to be your complaint?).  I don't see a problem with this- in fact I would encourage this especially if you're trying to help the flag carrier.

If your complaint is when players stack ammo by picking up the weapon they threw down to gain an advantage. From my understanding Epic forcefully crashes your game if you try to stack ammo using ThrowWeapon.  So you have to suicide yourself to stack ammo (or to get dual enforcers) and I don't see much of a problem with this either.  If people feel a reason to complain about that then I guess we can do something about it.

[PC] Keybinding Tutorial - Bind Throw Weapon 
http://forums.epicgames.com/showthread.php?t=648967