There is no privacy issue... none, nada, zilch, zero.
Scan everyone, every single person who wants to board... including crew.
You choose to fly, that choice inherently includes those actions, scans and measures required to get on the aircraft. To desire an end result, you must desire the means to acheive that end. In this case, you want to fly. That means you desire the scan, it's not invasive... it's welcome.
We need to stop pandering to completely unfounded claims of 'privacy'. You want 'privacy' stay at home. You choose, choose mind you, to go out in public... man up and accept reponsibility for the consequences of that choice. Images, scans, information requests and all sorts of other 'invasions' take place when you go out in public... the cost of choosing to leave the sanctity of your home.
Just my opinion.