Very small type at the bottom of their ads. Despite what people think, you are not required to stick a trademark sigil right next to your mark. I have been having this argument with people for nearly 20 years, and don't blame the lawyers so much as the managers who won't take the time and effort to actually think about what the lawyers are telling them.
I've also heard (from MS lawyers) that it's only important to have this at the first point of display of the logo, such as installer or splash screen. Does not have to occur everywhere.
Then that example can be applied to the Surface tablet* and any manufacturer's laptop -- no (TM) there.
But even then, what makes a hardware product different from an advertisement or a software? As far as I know, there's no legal text on the bottom of these hardware products either.
Check out Ross-Whitney Corp. v. Smith Kline & French Labs, 207 F.2d 190, 99 USPQ 1 (1953). Might provide some support for your position if you have to argue with the lawyers ;)
