Suggestion for additional instance marker

To add an ingame option ability to enable/disable a new marker similar to the existing ones that can be placed on mobs or players.

This marker would be on the tank, and can be enabled or disabled in the options menu.
Some players dont like being marked so take it off and some addons auto mark mobs taking it from tank which means cleaves can be taken by not so aware players.

You want to put a marker on the tank?

Is that so you can just watch him scream off into the distance and pull every mob in the instance while the healer is still buffing?