I’ve used the MTH part for about a year with no problems. Before that, I used cable ties…still do on PS2 steamers with the wireless drawbar. They aren’t easy to take off so I don’t think there will be a problem with them falling off. And I do believe they are supplied with new steamers. They are shown in some of the newer manuals.
Unfortunately, it only solves half the problem. I've got one or two locos where the front plug at the cab comes loose on occasion.