iDine/Rewards Network - RN and ThanksAgain interaction?

If you register the same CC on ThanksAgain.com as you have on a iDine/RN account, what happens when you visit a restaurant that appears in both programs (if such places exist)?

And on a side note, where can you find information about ThanksAgain's partnership with AA? I saw a signup about Delta here (http://www.flyertalk.com/forum/showthread.php?t=880389) but, although the website shows AA as a partner, I can't find it mentioned on AA.com

Also, is it possible to sign up for both Delta and AA versions of the ThanksAGain program?

Good question, I just signed up all 4 family members for TA to get the 1000 mile DL bonus (really just to extend our accts another two years).

Checked one of my RN accts and the Visa card is still active there.

I am pretty sure you won't be able to double dip two different TA accounts just like one CC can only be signed up with one RN provider.

When I looked up what was available in my area via Thanks Again, the only participating restaurants that appeared were there via the restaurant.com gift certificate purchase program. I don't see how one could double dip those with Rewards Network unless it's a matter of purchasing the gift certificate to get the miles credit via TA and then paying the balance of the ticket on a RN registered ccard.