XP: WWYD?

I haven't been on here in a whiel, but I also posted this over on the toddlers board too...What would you to with this car seat dilemma? 

DH and I are taking the babies (18 month old twins) to Cancun in a couple weeks and staying at an all-inclusive. We won't be driving anywhere aside from the ride to the hotel and then back to the airport. The hotel has it's own shuttle (more like a large 12 passenger van). For the flight we will not have purchased seats for the kids.....

Do I bring the car seats just for the rides to/from the airport? We went to Cancun with the babies last year as well, but they were still in their infant carriers and I had the snapNgo, so it was much, much easier.

In a similar thread from a couple weeks ago on the toddlers board, some posters mentioned these portable car seats (there's one by Eddie Bauer and another by Safety 1st). I don't think they make these anymore (I'm sure because they don't meet proper safety standards)....but I thought bringing something like that along would soo much easier. 

So...WWYD? Suck it up and check in the car seats (we have the evenflo triumph advance.....they're HUGE!)? Or would you make an exception for the rides to/from the airport?

Or option 3.....if anyone has those portable car seats I mentioned and is looking to sell them?......anyone??