[EricH]

Originally Posted by Fab.Master

what should be classified as "clear" above the flag/flag holder? is it directly above or around the flag within "x" inches?

Directly above for sure. The detector is right under the overpass.

And according to <R18>,

<R18> ROBOTS must use the LAP INDICATOR provided by the field personnel during all official tournament MATCHES. The LAP INDICATOR is attached to the stopper on the flag pole. When the FLAG is placed in the flag holder, the stopper will insert into the top of the holder. To accommodate the LAP INDICATOR, the area within a minimum 180—degree horizontal arc around the top of the flag holder must be kept clear of any obstructions within a 2-inch radius. This region must be kept uncovered and visible from above. To ensure that every FINISH LINE CROSSING is properly recorded, the LAP INDICATOR must be visible to the Lap Detectors when the ROBOT passes under the OVERPASS.[...]

(emphasis mine)

Thoroughly reading the rules multiple times is a definite advantage.