Just noticed this thread. I had both of my slingshot plastics break within a short time on location. I cut out a piece of Lexan and attached it to the underside of each broken plastic, put them back on the game and didn't have a problem with them after that. Kept the new slingshot plastics in the bag for the next guy.
Hobbit is long gone and I don't miss it a bit. Hard to believe this didn't show up somewhere during game testing.