I should have phrased that better. I knew they weren't hardwired. Because the 401, and the 301, and possibly the 403, I don't recall, have the single lead power cord that plugs in on the side, and then the separate foot pedal plug that plugs below the level of the bed of the machine, I wondered if the foot controller cord gets pinched.
The 401s I've had I put the adapter onto it, and slid it into the plastic case and it seemed a snug fit...
I think the trapazoid case definitely adds wear and tear.