I would be in favour of this if it were done the way CATSA handles flights to the US from Canada.

WTMD is primary for all lanes; during the periods when the MMW is active, there is a randomizer mat. Those selected are given the choice of a non-TSA style patdown, or the MMW.

A very small percentage of travellers is actually scanned, from what I have witnessed at various airports, and then only after they choose from a non-invasive patdown or the MMW. There is no indication however from the article that the US would go this route ie reduce the amount of people being scanned; it would just reduce the ability to self opt out.