If you aren't moving your position and you have a topographic map of your territory, and you have a line-of-sight weapon that doesn't need wind or range adjustments... then you don't really need to know where your target is in 3 coordinates, you only need 2.

I would expect that ambient lighting changes are harder to compensate for when selecting targets.

It is, however, terribly irresponsible to do this, since temporary reflectors like water puddles or a misplaced water glass can be inadvertently weaponized.

For small areas, an overhead water sprinkler would be much, much safer and not need aiming at all.