>> so easily misinterpreted outside of those disciplines.
I agree! "Open pollinated" does sound like "pollinated out in the open".
The first time heard the "promiscuously pollinated" usage of OP, I charged indignantly to the glossary on that OTHER site, only to learn to my chagrin that BOTH meanings were already entered.
P.S. A Wikipedia article gives your definition for "Open pollinated" .
But I'm sticking with the meaning used by seed and plant vendors, breeders and scientists!
Umm ... does ATP HAVE a glossary?