Not all drifting during a final kick is intentional - and when it's not intentional it's not cheating - just something everyone else on the home stretch any given race better come prepared to deal with. Drifting is not forbidden during the other parts of the race, so why must track running constantly embarrass itself by constructing these post-race cry foul situations?
Every now and when we see runners stumble on the last hurdles, and everyone watching immediately understands that the explanation "I was so tired that I no longer had full control" is true.
Runners are expected to come prepared to deal with such, with competitors ahead of them stumbling on a hurdle, or bunches of runners ahead of them tripping each other up, so as to have jump over or go around them, it's part of the sport. If you're not running up front from the start you have to accept that shite can happen. Go hard at the front, take your chances in the back, or stay home.
The same should go for drifting during a final kick. It's only cheating if it's intentional. There can be unintentional drifting during all out final efforts because of even minor sudden bursts of side wind, leg niggles, foot niggles and other forms of temporary or permanent uneven biomechanics. Everyone who's ever kicked so hard that they lost control over their running technique knows this. Hence every runner in a race needs to come prepared to deal with those situations without crying foul afterwards.