As a retired ATC worked in New Orleans Center, Jacksonville Center, Miami Center and Pensacola ARTC, I had many such occassions to warn pilots of other ac on my radar that we were not working and weather was marginal. There are a lot of foolish pilots still flying. Most are new pilots and not IFR rated. As controllers we do our best to warn pilots that we are working of unknow targets on our radar. I do not know what happend here unless that out lying airport did not have radar. Thanks to the jet pilot professional that took over the job of helping out here.