I think you're right, Mark. I'm going to go get a magnetic box today!
I had another key fob break on me while hiking this week. I need to figure out a carrying case for them while they're in my pack so they don't get smashed. The key portion broke off and fell before I realized it when I took my keys out of the pack. Thankfully, I had a second key stashed in my jacket, just in case, and was able to find the broken key within a few minutes of looking.
I sometimes think it might be easier to just ditch my car and go back to my bike and trailer!