To be perfectly honest i dont see how they can check for a firmware on a DVD drive... I think they know that too.
They can do it wih great ease tbh. Its not hard to dump the firmware of a drive back and forwards if you have the operating system under your control (which MS do).
But its not really an issue, MS actually only really banned people from live last time round to stop people cheating on live and nothing to do with piracy. Live is their cash cow and anything that makes the system unfair would wreck it for them. As long as people dont make a modchip that lets you change the game code or open up the operating system and rom chips on the motherboard like we did last time I doubt theyll actually do anything.
Theyve made the process difficult enough and the consoles expensive enough to scare off the vast majority of the population so its not a huge issue like it was for the cheap and solderless modchips of the original xbox.
Either way Ill be chipping mine as soon as I see a little more info from the mod chip community regarding standard features and how they will handle Microsoft changing the disc formats to block the current gen of hacks.