I have played long term on several servers in the past that had Drop Backpack for PVP. The biggest issue that every server faced: Raider only brings 2 items with him to raid. Gun and Pile of ammo. He then hides a sleeping bag in the area. Attacks your base, you defend but everytime you kill him you get nothing of his. He respawns back nearby with his same gun and ammo. This cycle can continue for hours until the base owner has to log off or is just pissed and leaves.

By having the toolbelt drop, you are guaranteed to get whatever weapon the enemy raider is using to attack you if you kill him. Thus changing his style of attack next round or possibly scaring him off for that day.