No, they just pay attention to each other (some combination of reading the lines, reading between the lines, listening to loose lips, maybe even a spy or two) and copycat + frontrun.

The fast follower didn't have the release sitting in a safe so much as they rushed it out the door when prompted, and during the whole development they knew this was a possibility so they kept it able to be rushed out the door. Whatever compromise bullet they bit to make it happen still exists, though.