Yes, yes you do. The ridiculous lawsuit that Apple is currently waging against Samsung is a prominent example. Frivolous waste of time. "Let's patent a rectangle. Wait, a black rectangle with rounded edges!" Good thing no one told any TV manufacturers about the no-rectangle patent! Silly.
Don't get me wrong, though. I work on Macs every day; love 'em. But I think the platform wars should be over by now; being able to use *any device or OS or application should be the focus, shouldn't it? (For my part, I'm enjoying the flexibility to create, code, whatever on open and expansive Android devices in addition to my Mac these days. And I'm grateful that OSX is now based on a BSD variant.)
http://www.teleread.com/copy-right/jailbreaking-dmca-exempti...
But that is no reason to be complacent about the issue (or to think that this legality is written in anything but sand).