Yes, I understand that, the rule doesn’t make sense from a competitive point. I imagine there’d be somebody local that would happily supply something (fired clay, maybe,) at cost for an opportunity to sell stuff.
Maybe it’s just a non-serious local event, and finding the rocks is half the fun.
But really! lol.
Simple- get a bigger collar. Also maybe a bigger suit of armor.
Or maybe just an armored vehicle to go around in. I hear they have special golf carts, even.