Interesting. Very interesting.
Here, a SG is encouraged to flag IG. It's very possible that the R is with the QB and can't look up to see something like where the balls lands/is thrown to.
I've even thrown IG as a deep official! And before anybody (you know who you are!
) says anything, yes it was justified.
It is now more recognized that SG have knowledge of the R position, and know what the R's responsibilities are if help where required.
Further example: We have the downsbox discreetly signal before or beyond if the QB throws a FP near the LS. The R might be yards away from the FP release point. the downsbox is potentionally in the best spot to see this foul.