No, I just went back and checked, on the booking page at the bottom it asks for full mailing address, and United States is prefilled in the drop-down country menu!
Actually nowhere on the booking page or leading up to the booking pages does it say this offer is only for UK residents. The only way you would know that, as far as I can tell, is by the URL.
Nobody seems concerned about whether they will honor the 7/4 rate glitch for less than 7 nights. Whatever a Loews agent tells me on the phone probably isn't going to mean anything to the front desk staff.
Are the Universal hotels the same as Disney in terms of AAA (limited number of room available at that rate)? I am a AAA member with card...if this rate is not honored when I check in, I wonder if I could then show my AAA card and be given that rate.