When you write "free from theft", do you mean copying the software tool in question or copying the hardware design? If it's the former, then this hypothetical open sourcing of the tool in question would let anyone copy it freely, so the question answers itself. If it's the later, then the answer to that is, "only if those doing the copying get caught." If they keep their designs secret, and do not open source their equivalents of tools like the one in question, then they won't get caught, right?
I was thinking of a situation where they all went open source, but yeah very valid, and even if they all have mutual agreements to open up it doesn't stop an outside party abusing that agreement.