It could also have been TSA as they routinely open bags...and that is likely what AA would argue. Unfortunately, you're going to have to take this squarely on the chin.
And I have to ask...why 10 credit cards? I have two total (Amex and mastercard). Why the need for so many...and these are the auxiliary cards? For the future I'd strongly suggest that that is part of the problem you're going to be facing.
Best of luck with getting this all sorted out.
Cheers.