I agree with that. I used to be extremely paranoid. Now, less so. But I did have an experience once that reinforced my paranoia: A local prominent business woman visited first startup under the pretense of being a potential investor (which gives her an automatic out -- investors don't sign NDAs). She watched my demo, took lots of notes, asked lots of questions, left, and then called me three weeks later to invite me to breakfast at some fancy private club. I show up (she's wearing some sort of see-through shirt which freaked me out a bit -- I was suddenly worried she was going to try to seduce me) and then, with a straight face, told me: "I have complete notes about what your product is, the direction you're taking, and your business model. I also have a team of great engineers who recently left Sun who ready to start coding tomorrow if I give them the go-ahead. Unless you hire me as your CEO immediately, I will steal your idea, launch a public campaign to discredit you, and make sure you never work in this industry again."

I laughed because I was sure she was kidding. Turns out she wasn't. I politely declined her offer and walked out the door. She told me I'm making the biggest mistake of my life. I probably spent the next two months being in such a paranoid state that I was pretty much useless as a contributor. It turns out she never did follow through on her threats. But I learned then that even someone with the worst of intentions can't necessarily take someone else's idea and turn it into a reality. That's when I started to relax a bit when it comes to NDAs. But, that said, I still ask contractor programmers to sign them but what I ask them to sign is so amazingly simple that it's more an agreement to respect each other's ideas.