@299792458
That sounds very reasonable. I checked some things as well, and a few details seem to support it:
-There are cables on the ground, near the chairs (289, p10). It doesn't show a cable connection from the chairs outright, but they are definitely visible on the floor. If the restraints are a measuring device, the cables are probably the first step to transmitting it to the radar.
-The chairs and restraints are different from the ones they used when they initially captured Kaji & Yokoi. Although it could just because the other setup (288, p7) was too flimsy, and possible for them to break out if no one is watching.
Another thing is why the crew members even bothered to allow Kaji & Yokoi to watch the match. Allowing them to watch might help them if they were to break out by some chance and later return to Gakuto's side, or perhaps even right now, if Kaji/Yokoi have a communication device like what Hachina has. It would make sense if they did it because it ultimately had a benefit for them, outside of teasing/torturing them.