The bottom plate of the E-P1 (and E-P2) is a very thin aluminimum pressing. The tripod screw mounting is fixed to the inside of the thin metal via way of a small mounting plate. It is a very poor pieced of design. A better design would have been to extend the chassis of the camera to contact the bottom plate and have the mount attached to the chassis.
It is easy enough to push the distored plate back into shape and the design of the tripod mount has a lot to do with the risk.
As for swining mounts, the soft rubber plates are the best, followed by cork and then the hard rubber ones. Unfortunately you rarely get a choice with a particular make of tripod.