I did several of the things mentioned above, I did not sign it until they dragged me into the bosses office and made a big stink (six months after it was issued)and then i amended the copy I signed and the one I kept, because several of my clients had been MY clients when i was "bought" by the firm who wanted the noncompete, and I knew full well that if I left, these clients would follow me. They might not terminate the work they did with my old employer, but they would still call on me to provide services as long as I was still active in engineering. I did agree not to actively seek to cut out my old firm, but then i knew I did not have to. When I did leave for another state, the work my old firm did for my clients dropped to almost zero, although in one case there was a trend in that direction even before i left due to internal issues with that client. Since I went out of state, the issues were moot - they would not call on me from this far away.
one other note on this topic, we once had a client, a hospital, who wanted us to sign a "non-compete", saying that we would not do any work of the same or a similar nature at any other facilites for a period of 1 year...this was not, mind you, anything fanc. It was replacing underground fuel tanks, and we already had half a dozen other jobs doing the same thing at other facilities. We informed them politely that we could not stop doing structural engineering at hospitals just because we worked on one little job at thier hospital. we did not laugh till we were in the car. We also did not sign the contract as it was written.