1. Whilst driving a Police Car would be absolutely hilarious and not-very-Bungie, that's the same thing that I thought about playing as Johnson with a VISR in Firefight. Look what happened there. It's a fricking video game, if Bungie decides that it works for their game, they'll do it. Whilst I don't believe it'll happen, you're more than welcome to believe what you want until the game is released and we all know for sure.
2. The reason the two presenters were asking such "stupid questions" wasn't because they've no idea what's in the, game, they're asking that to confirm to casual and hardcore gamers, and even perhaps to people who haven't ever heard of Halo before, so would've been confused about certain elements of the game. They're there to ask questions, even if they know the answers. That's their job.
3. What's with the huge lack of common sense (lol irony), and logic in this thread? Bungie have said that a lot of things were changed, and scripted differently for the E3 Demo of ODST. So if somehow, Police Cars were drivable, that would count as something that Bungie would want to keep secret and surprise people with. So yes, they would hide the Hold RB function if that were the case.
Even still, I wasn't aware that basic-training for ODSTs now included "Hot-wiring for the 26th-Century Vehicle 101".