Rock Band 2

[Squeek]

Wow, chill out.

All you have to do is look in the patent registry to see if a patent exists for your product, or hire a patent lawyer to do it for you. It takes very little time to verify that nothing else exists in the patent registry.

For whatever reason, these companies either aren't trying hard enough to look for patents or aren't even bothering with them, and they're getting sued for it. All you have to do is spend a little time looking, find out if there's a patent, ask the patent owner if you can make something based on the patent, settle for an amount of money to pay them, then go for it. It'll be a lot less than what the courts will fine you for if they find you guilty of patent infringement.