I'm heavily into Victorian Science Fiction gaming myself. Fortunately, I can scratch-build just about anything I need. It's unlikely I'll get sued by the contractors who built the Martian combat tripods or Her Majesty's steam juggernauts. However, a lot of the folks I know are into historical or pseudo-historical (NATO vs. Warsaw Pact) tabletop gaming, and I can see this coming home to roost for them.
Well, if they're going after plastic models, they'll go after small metal miniatures next.
The interesting thing is if they'll go after someone with a board wargame that simply has cardboard counter for a squadron of B-17s or something.