The "cheat neutral" concept is not a perfect analogy to the carbon offsets- and may make the idea of carbon offsets seem more absurd than it is. Analogies let us see things from new angles, but we should not base decisions on analogies.
The biggest difference between Carbon Offsets and Cheating Offsets is that as Greeniac40021 pointed out, we cannot reduce our carbon footprint to zero. Some people- and the satire rests on this point- think that cheating on ones partner is NEVER ok, and that the whole concept of cheating is always morally wrong.
I do not think that we can say the same for carbon emissions. Even our breathing causes carbon to be emitted into the atmosphere- but no one would say that breathing is morally objectionable- that would be absurd. Rather, in a balanced environment, we breath and plants respire and ideally it would even out. So in some cases carbon offsets may attempt to mimic this concept- if we emit more carbon then perhaps to remain "neutral" we must plant more trees or do other thing that help reduce carbon. I'm not sure it really makes sense for individual people and individual actions to be "carbon neutral"- that would be similar to saying that if you don't own any trees you can't breathe because the carbon won't be offset. Maybe it would make more sense to try to achieve a balanced world, and we could achieve this both by reducing activities that emit carbon and increasing activities that reduce it. Donating money in the form of carbon offsets could be one way to support this effort, as long as the organizations are authentic and effective, but I'm not sure it makes sense to talk of a correspondence between the airplane ride and the donation.