Yeah. They'll add it in conference committee, where, after the initial vote, they reconcile differences in bills between the House and Senate versions. It goes back for a quick final vote in each chamber but that's usually considered procedural as I understand.

I don't know for sure, but somehow doubt that it's uncommon. More likely, the changes snuck in aren't enough to raise significant ire so they get away with it. And if if people figure it out and are unhappy, there's always plausible deniability: "Some intern added it; it wasn't supposed to be there."

umm... a rubber mallet?

More seriously, Google has a history of not even using cases some of the time -- at least not cases as most people think of them.

As I recall, they're even using custom motherboards and such, so custom cases (or special racks if they're still doing the caseless thing) to accommodate 12 disks per mobo seems very reasonable for them.

Sadly, tacking stuff on isn't limited to the budget bills. It happens routinely.