It struck me, although I've never had to invoke the guarantee...
What if I wasn't 100% happy, but then HI comped my night, and that made me 100% happy? Maybe I should insist they take it back--but then I wouldn't be happy...it's a conundrum.
-Hayden
P.S. Like one of the above posters, I'd avoid HI Atlanta Midtown, too. Great, friendly, staff, but horrible, motel-like HI. Sort of HI meets Travelodge, albeit with good MARTA access.