The only down side is you now have an amp without enough cooling for demanding jobs, IE, PA use. Someone grabs one, tosses it in their rack, cooks one after an hour, and calls you demanding a new one under warranty.
But just tossing out ideas. If I were to build an amp specifically for HT use, I would design it with a lot of metal in the heat sink to help absorb the heat generated by the loud passages. Instead of thermal swings of the heat sink from say 80° to 200° back to 80° in just a matter of a minute, they might be 80 to 120 to 80 in five minutes. There would be no need for a fan to increase fan speed to help cool it down due to excessive heat build up, because the temp would be kept more consistent.