So... ONE group out of the hundreds of throusands of people who attend WDW parks every day proves that the GAC is "too widely distributed?" Sorry, but that's nowhere near the realm of statistically significant.
No matter what system is in place for any given situation in any society, SOMEBODY is going to figure out a way to abuse it. For my money, any establishment worth existing is going to err on the side of helping a few people who don't actually need it rather than err on the side of not helping any number who do.
GAC is absolutely necessary - never said it wasn't. I was just offering a little insight to OP as to why a few CM's seemed grumpy with the GAC.