That someone was me. Unfortunately, it is the dimensions that would get you from being able to check it as luggage with no fee. The fees are just not cost effective if you don't plan on leaving the bike in Cozumel as you would have to pay the fees on the return also. Now, if you had several people traveling & were able to break it down into multiple boxes of less than 62 linear inches each, you might be in business. Of course you'd use up your baggage allowance & have to pay for an extra bag if you wanted to take clothes, scuba equipment or anything else, so you're back to square one.
If you had someone that lives there & had room to store a bike, that would eliminate the return charges. Or, you could buy one at Mega, Chadraui or Elektra & do the same thing, but you'd probably be spending $150-$200 for a bike. Haven't checked prices or availability at the new Sam's yet.
No easy way...wish there was.
Mike