This is my first time on the forum. So hello to all
I have a 2010 Cooper S which is truly a blast. I previously owned an 04
Cooper. I recently had the airbag light come on and the seat belt warning
light when a passenger got into the car. Has anyone heard of this happening?

 

There are a number of sensors that feed back to the Cooper's air bag control computer. You likely have a sensor, a connector or CPU that is defective. Have you hit anyone or visa versa? You may have damaged a sensor in the bumper or elsewhere.

I had to have my seatbelt replaced (it has a sensor) because the seatbelt light kept coming on even though I had it fastened. Your '10 MCS is under warranty, so I would suggest getting it fixed ASAP.

 

Yes have it checked out by the dealer. Shouldn't happen.