some of it's made up, and some of it can't be quantified

This infographic on Firefly is fun because all things Firefly are fun, but I noticed this bit particularly:

So, if the makers of Outlaw Star had sued alleging that Firefly was substantially similar because a girl with unusual abilities given to her by the government who was secretly (and nakedly) transported in a cargo box was revealed in a cliff-hanger in the first episode--what should the result have been?  I actually find "coincidence" perfectly plausible--but a lot of strike suit plaintiffs don't.