Well, we have front and side; and nothing went off. I guess we were lucky. The hair barrette on the back of my head snapped and stung me; and I had to walk a few blocks home in freezing weather while husband dealt with police. But no other physical injury.
And we got a very nice loaner for the WEEKS it took them to get our car back in shape. We understood that it was about 6K worth of damage (I don’t know if we could have sold or traded the three-year old the car for that much, just before the accident happened) but the woman who hit us had a good and accommodating insurance company!
All’s Well that Ends Well.
On most cars, the trip sensors for the airbags are in the nose and sides, not the rear.