A cautionary tale from the iPhone market in which a successful app developer discovered that an unscrupulous development house included his product in their portfolio.
I can attest that this happens. I have had direct experience with a component that, in retrospect, was almost certainly stolen and reverse-engineered. When confronted with irrefutable proof that an identical component was in the hands of a competitor, the Indian subcontracting company said "Wow! They must have stolen our component!" (There's no proof they were lying, but the circumstantial evidence was substantial.)