In Dynmap (I'm sure you're sick of the comparisons, my apologies) there is an option to "hide a player from appearing on the map if they are in a sky-light level less than: [integer]" allowing shadows, overhangs and underground.
For servers with a PvP focus or players concerned about stealth/privacy, this has been an excellent feature.

It would be greatly appreciated to be able to set a "sky light" level required for players to appear on the map, so when indoors or under cover their location isn't revealed.
Many thanks for your time and consideration!

Implemented in 3.4