I can't find anything online about that at all, and we're not talking dark ages - this site was running then.
If anything did happen, the story has been... exaggerated. Cops don't arrest people from conventions for selling blueprints of starships, that's absurd, and illegal. At most, CBS/paramount representatives might rock up with important looking paperwork to try to shut people's stalls down or frighten people into leaving, or do some research for C+D letters later.
Disney have always been famously hot on copyright infringement and yet bootleg Star Wars merchandise, art, costumes, etc etc still abound at conventions. The internet is crawling with people selling this stuff too. They can't ever officially endorse it (hence the fan film guidelines about making it yourself or buying licenced costumes/props, no buying fan made) but they are stoically ignoring it.