Dell ships laptops with tons of Dell software, as well as tons of third-party software. Do you really think that, if they wanted to, they couldn't just update one of those pieces of software to enable remote installs?

Hell, Dell has shipped more than one bug that allowed attackers administrator-level access or worse, I wouldn't put it past them to come up with some kind of asinine feature that not only lets them push new software/drivers/whatever to the machine, but lets attackers do so as well.