User blog comment:DCFreak22/Mount Justice Authorized Guest Designations?/@comment-4473295-20120126213101/@comment-1038387-20120129102705

Unknown. Those rights things are tricky - there were several characters who were off-limits for JLU (Ted Kord/Blue Beetle, Black Lightning, Ronnie Raymond/Firestorm). With Blue Beetle it was a (failed) late 1980s radio show or something that had the broadcast rights, and with Black Lightning they didn't want to pay royalties to Tony Isabella, according to McDuffie. But the three of them did show up in The Brave and the Bold...

Maybe the rights were with the bombed Adrienne Palicki pilot, or the bombed JLA movie. Maybe no-one outside the WB legal dept. really knows how this stuff works...