You raise an interesting point. First, the flush tower drops by design automatically; holding the handle down has no effect. This was probably done intentionally to prevent users from over-riding the 1.6 GPF. Here in San Diego County, there is a toilet rebate program, and to qualify for the program, one of the requirements is that the toilet is designed to PREVENT flushing more than 1.6 gallons under any normal or abnormal circumstance. The flapper must also withstand testing with chlorine bleach and "2000 flushes" , hence the red thermoplastic rubber.