As an admin running a few servers we on occassion do events where we hide (insert bury) a number of caches and then advertise on the message of the day and hourly notice of 'thar be treasures in them thar hills (or beach)' with a vague grid reference usually using POI's and other navigational aids to assist in locating the specific grid square/s

Anyway, suggested this in the past as a base game thing and not something server admins/owners run if and when there's enough people online. /shrug

but its a great idea, so +1 and a double thumbs up from me

(ps: metal detector used for base raiding to fine traps/mines)