This is an idea I've been playing with for a while, but never posted it on boards. tbh, I think it would allow to equip bots/casuals, without allowing selling/stalking, and it's the tag [guild property]. Initially I had this idea for keys, port necks, and similars, but I guess it can be used also for normal drop.
The idea is an item being [guild property] can be traded, but not droped, between members of a given guild. IF a character with [guild property] items leaves the guild, these items poof, pretty much like faction bound items.
So, obv making all items [guild property] is not that good idea, but, maybe, making common drios (that usually rot, anyway) this tag, may be interesting. Also, would allow anyone to loot keys. Atm it's a problem when the char who had the keys is not online/leaves the guild. With this system, you could just transfer keys around as needed, but just in between a guild, making imposible selling keys like upper thaz, Inner prison, CoD, etc.