Legalities of Commercial TCs (Star Wars, Trek, etc)

What's the whole legal deal with making TCs of other, popular sci-fi stuff? People seem to be doing it and haven't gotten in trouble yet, but I'm still curious. I personally prefer to do my own work, but I'd like to see plugs of Star Wars, Trek, FarScape, StarCraft, etc, and wonder what would happen to people if they actually succeed and get noticed by big Uber Companies. (StarCraft in particular, since it's a game in the first place and Blizzard Entertainment is more likely to browse gaming forums than TV companies)

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Technically, I'm in violation of copyright. I make sure to say, in all my documentation, that SFA is freeware not intended in anyway to infringe upon Paramount's legal properties. It's my understanding that Paramount is pretty lenient towards fan efforts, as long as they're not making any money (which plug-ins don't), and as such I'm hoping I'll be able to fly in under their radar. However, if I ever get a cease and desist order, SFA goes bye-bye.

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Entarus,

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