This is the only way to access the instruments, and assembly of scaffolding is not trivial, requiring advance coordination with college physical plant personnel. Note that scaffold must cross several tiers of seats, requiring special leveling jacks.
Coves are very tight, access is by removing ceiling tile.
Individual instruments can only throw to a limited portion of the stage, and adjacent instruments can interfere with aim and shuttering. Finally, here is a picture of GoferJoe doing a regel.