Is right wrong?

CARS today are much more sensitive to noise and vibration, and tyres wear in relation to their position. They typically wear on the outside shoulder and in the direction of rotation, so swapping a tyre from one side to the other means it is rolling in the opposite direction and that might set up an annoying vibration, which may be why Ford don't recommend it. There is no reason you can't swap tyres from side to side if that's what you want to do. And using plugs isn't illegal, but certainly not recommended. A good repair is a patch-plug -- a patch that repairs the tyre on the inside and plugs the hole to keep out moisture.