I disagree that it's only big companies you need to worry about. There was recently a thread here on HN[1] about an open source flight plan project shutting down after being threatened by legal action from a small company that provided a similar service (and had some patents around it).
But regardless of the specific probabilities of any one startup getting sued, I still have a problem with a system where the government will harass you into bankruptcy on behalf of an incumbent corporation if that corporation decides they want you out of the way.
It's like a landmine in the middle of a football field. I probably won't be the one who loses a leg but it's enough of a threat to think about seeing if there's a better field to play on.