You might think this is funny, but when I first started doing the filters I even had two of my vendors sign non-competes before my first order. I had a new idea that I had to explain to them and I didn't want them running with it. I had an ultrasonic company help me design a task specific ultrasonic machine and they had to sign it too.
I used to sell franchises (another type of business) and we had lots of people come to stake our business out and then go try to open their own. If we told anyone anything they had to sign a non-compete.
Did it work?
Yes, but only because it discouraged the competition, not because we could enforce it. It just costs too much money to enforce it.