Sure, I might enter the singles line to get up the hill faster than I would have otherwise. But if I am not slowing anyone else down (which I am not), why do you consider it cheating? The definition of cheating is to gain an advantage BY ACTING DISHONESTLY. Simply gaining an advantage is not cheating, in and of itself. Using something as it is supposed to be used is not cheating. Being first isn't necessarily cheating. If the other party is fully able to gain the same advantage but declines, then that is their issue.
I am thinking that if most people really are singles then we need one groups line and several singles lines. But, that would negate the advantages currently held by folks that ski in groups that take the singles line shortcut because it would give everyone the green light to do the same thing.