It really amuses me that all you Divers in the USA are whining about excess baggage charges, when you already get far more generous baggage allowances than the rest of the world!
In Europe, we have had a checked baggage allowance of between 20 and 23 Kilos (that's 44 - 50 pounds, depending on the airline) for as long as I can remember, and if you go above that, you pay an excess per kilo - which can often be as much as 1% of the full First-class fare
per kilo.
Many of the cheaper airlines in Europe now charge a "check-in" fee of around US$25 per checked bag each way -and paying for 2 or even 3 checked bags does not increase your total baggage allowance, which stays at 20Kg.
From what I've been able to gather (primarily from the
SeatGuru website), on flights from the USA to Mexico, Continental allow you one bag up to 23Kg (50 pounds) for free, and a second one for just US$27 if you pay online. In addition to that, you get a generous 18Kg (40 pound) Carry-on allowance - in the rest of the world, it's generally between 7 and 11Kg.
Most of the divers that I travel with manage to keep their checked luggage to under 23Kg total - and some travel with 15Kg or less (including BC, Regs, Fins, Wetsuit, etc., etc.). Those with lots of Camera equipment accept that they will have to pay excess fees, and allow for it when planning the trip.
I'm going to Raja Ampat in Jan 2012, and have been told that the checked baggage allowance on the flight to Sorong is just 10Kg (22 pounds). Although I doubt I'll manage to get my weight that low, I'd be surprised if I have to pay for more than about 8Kg excess - when you're travelling to somewhere hot, and are going to be underwater most of the time, do you really need to pack more than a couple of pairs of shorts a few T-shirts, and some sunblock?
Get real, people - learn to travel lighter, and stop whining!
Neil.