[Sacred]

My counter-suggestion:

Not Kosable if someone vouches for you having grabbed it from corpses or map objectives.

If it turns out you were a T with the item, valid sus on the voucher(s) (Vice versa if the voucher was a T). This allows you to kill potential traitors lying, without kosing an innocent on the spot)

This also gives players the opportunity for getting secret knives/weapons/detective drops without having to be punished for it, while also acting as a middle ground where if nobody can vouch for you, you can be KOS (assuming not proven).