24 hours bottle-to-throttle does sound excessive but, IMHO, the current regs are inadequate. 10 hours isn't always enough for a full recovery from a good session, and we all know how often the guidance of "no more than 2.5 units in the preceding 24" is ignored!
The most troubling scenario I've typically encountered is when authorising crews from a distance, ie after an overnighter away from home base. It's 99.9% certain that the crew will have been out on the p*ss, however the Auth has no option but to take the crew's word that they're "fit-to-fly". Whilst my trust in crew's has never (to my knowledge!) been abused, this will catch someone out someday - guaranteed!
God, I sound like a doddery old killjoy...