Dunno... if I just randomly show up in Namibia trying to use a credit card - and it gets declined - and then a few days later I show up in North Carolina trying to use that same card, my bank would probably decline that charge too... Whether you think Hilton should be doing that depends on whether you think Hilton has a right to protect itself and its customers against fraud.

Now, if your gift cards are repeatedly being declined in the US, then I would also query whether the front desk agents are processing them properly.