I had the rivets sheared on the rudder stops also when parked in Utah during the first week of Sept. A front went through and the wind shifted and it got gusty. I had a pvc rudder stop on the pilots pedals that came loose. I replaced the sheared rivets with #8 bolts. Fortunately no damage to the rudder occurred. I now also put a rudder stop (the red one Avery sells) on the co pilots pedals.
RV7a N967BT 1900 hrs.
RV10 N143EB 960 hrs.