A lock and chain solves the dinghy problem most of the time ,especially a disc lock.
Kids sometimes play with unlocked dinghies and forget to tie them back up. It's too much of a temptation.
Meanwhile clean your paintbrush on your dinghy so it s doesn't look like something easy to quickly sell.
I once had a fancy set of oars. They dissapeared quickly in Frisco Bay. Since then, I've made all my dingy oars out of driftwood ,
plywood and plastic drums found on the beach, and wire or chained them to the dinghy, to keep them from bouncing out or being borrowed. They
work just as well as the fancy ones, but I've never come back to find them missing.