My wife's car had warped rotors about 10 months ago and would vibrate very bad when braking. I advised her to get it fixed, but she did not.

Now today I got to drive it and there are no more vibrations. Apparently the brakes pads surface finished the rotors in all these months...

 

Not sure about your case but gnerally if the rotor warped it tends to get worse overtime.

If you put in new pads and do not break it in properly, the pad material can become embeded to the rotor unevenly and causing it to vibrate. Overtime, this problem will eventually go away when the rotor surface is smoothed out.

 

You most likely had embedded pad material on the rotor surface. Rarely do rotors actually warp.

 

nope. not new brake pads. Actually I checked and there is about 3mm left now.
Last time brake pads were changed about 50,000 miles ago.