Also, there's value in sticking your head in the sand since if you know a patent exists but don't think you're infringing but then lose an infringement case, you're liable for treble damages (IIRC, IANAL, etc).

Every employee handbook I've seen that has mention of patents has said ``thou shalt not go patent surfing, and if you do, only ever talk to your patent attorney. Oh, but do file lots of patent applications!''