One of the pictures clearly shows Edison plugs (i.e. normal 120V plugs).
The little box midway does have switches. I would hope it has a relay scheme to prevent powering disconnected lines, but I rather doubt it does. I suspect they just say in the instructions that you have to switch off the lines until they're connected to the generator. The cord looks pretty dangerous to me, and I would think it may not past muster with the CPSC or similar agencies...but it's hard to know for sure without knowing what all is going on in the box in the middle.