On a fairly pedestrian upper Midwest commute to work in my pressurized piston twin a couple of weeks ago, I found myself being bounced around sufficiently that my head hit the headliner a few times, but the autopilot didn’t disconnect or anything like I have experienced when I felt obliged to make a PIREP in the past for such. After it calmed down, I poked around on my (fairly new) Sentry AHRS (which has a recording G monitor). It said that I was in +-2.4 G for around 10 minutes.
I always wear my seatbelt on commercial flights, but flying an airliner and having passengers bouncing around in the cabin in similar conditions is a terrifying idea.