I bought 10 $50 cards using Topcashback.com weeks ago when the offer came out and not one tracked for the promised 2%. I filed claims against every one but that usually results in nothing.
And the bookings I made using the cards on TCB got (as per the terms) zero- though I also tried MrRebates and am waiting to see if that tracks because their terms do not seem to explicitly exclude gift card bookings. So figure you are likelylosing the cashback on bookings and probably won't get any on the cards to offset it.
And by the way family members have more than 10 Amex cards but when I went to buy more the orders were cancelled and Hotels.com said there is a $500 per household limit using the Amex offer. Not sure whether they made that up or not.