From personal experiences:
1) Thrown from a horse on a hunting trip. Horse ran off with everything I didn't have in my pocket or on my belt.
2) I got bounced out of a raft in white water and my survival kit (in a waist/fanny type pack) got caught in a snag preventing me from getting back in the raft. I had to ditch it or drown.

Lessons learned: 1)PSP UNDER an undershirt (neck wallet) or in pants pocket. 2) Shoot all horses, and walk.