No one has touched on the customs issue --
Some manufacturers (have no idea if it applies to this case) have worldwide product versions and USA product versions and the do not allow the worldwide version to be imported to USA. Also warranties are no good in USA. Cameras are major issue for this. This sometimes called "gray market import."
Believe as far as custom duties -- this would be lumped in with the total personal $800 exemption

I believe that would only affect an official dealer.
I don't think that corporations (yet) have border guards preventing people from bringing in their own property!

They don't allow a Mexico dealer to sell and ship a product to the USA, or vice versa for that matter. It's more about protecting a dealer territory than political motives. Agree with others, sell the Plasma, don't bring it home. A 46" LCD or Plasma is pretty cheap these days.

OT, but the issue of moving items such as large electronics from country to country usually voids the warranty. Some companies go to even more extremes, a Lexus or Toyota purchased in the 48 states will not be covered under warranty if you move to Hawaii for example. I don't agree with this policy, but its more common than one might think. So with that in mind, and given that a 46" Plasma or LCD is worth maybe $700.00 for a cheap one from a USA dealer, it seems hard to justify spending a large sum to bring a set that was won in Mexico back to the USA.

In the Nikon/Nikkormat days, custom agents would sieze Nikkormat (Nikomat) if brought in the US by an individual. This has been true for other cameras also.

And yes custom agents do protect corprorate interests.

I would agree to sell it, if you hadn't intended to buy a plasma anyway, then it would just kill your power bill (Plasmas suck up a lot of power, and I doubt any raffle plasma would be of the very newest highest quality right now fresh on the market thingy ;) )

I would try to sell it, and do a MR with the money you're getting ^

Using CO's excess valuation policy as an example, it looks like the price for excess valuation $1 for every $100 in excess of limitation of maximum liability.
However, the policy specifically excludes fragile items, which include electronic items, so OP is still out of luck.

Don't forget, you'll also need to reclaim the box, haul the box through customs, and recheck it at IAD.

Best is to ask the casino to ship it to you, give you a cash or other equivalent, or sell the TV before you leave.

If you check it, don't expect to see it again, or for it to be working if you do happen to pick it up on the other end. The chances of theft are high, and so are the chances of rough handling. If you have to ship it, it's going to run you hundreds of dollars

Update
 

Thanks as always for the feedback. Wanted to circle back and let everyone know how it went.

First of all - we did consider trying to sell the TV before heading back up to the states. Right after we won it, tried selling to people at the casino, best offer we got was $150 (TV worth about $800 - $900). No takers at the hotel (LM) either.

Looked into FedEx (standard ground) to Chicago and it would have cost about $475+ Tax. Decided that for that amount we'd roll the dice and try getting it back to the states ourselves.

Luckily, this was the 3rd "bag" I had to check, and was able to get it on the plane with very little issue (other than carrying it around...awfully heavy for a "slim" TV). We arrived in DC, picked it up quickly (came on the regular baggage belt which was a surprise, but at least it was upright). Went through customs without issue, they said it would be covered by the tax-free exemptions in the code. Rechecked at IAD and picked it up at the over/odd size luggage staging area when we got to Chicago.

Overall the box made it in great shape with no visible damage. The box was opened and a note left by the TSA (for our safety, of course) to make sure it was on the up and up. Was very pleased with the ease with which this went off, and would like to give UA a pat on the back for making it pretty painless and to the TSA for not stealing our prize!

Thanks again for the pointers, everyone!

Dan

^ Congratulations on the prize!

Coming from Mexico, he's lucky nothing got "added"...

... or decorated with bullet holes.

That's great, but when you plugged it in, did it work?

Because not shipping a plasma upright can damage it.

You are lucky it wasn't a guitar you were trying to check :D
I think because of the built in handles on these boxes, it is very likely that the TV was always upright. Easier for handlers to move it that way. I cannot believe it was put on a belt and it had no damage! Congratulations!

Most plasma TVs have warnings that they are only to be transported in their upright position. I would have thought the chances of having a working plasma TV at your destination approach zero if shipped as luggage. As others have said I would have tried to convert it to cash. You were very lucky. Are you sure this was plasma TV? LCD/LED TVs are not as fragile as plasma.