I have always opted out of these scanners as a matter of principle. (To wit, I think it’s an erosion of privacy.) But you should know that the TSA changed their guidelines such that granting a request to opt out is effectively up to the discretion of the TSA agent at security. Their new guidance says:
>While passengers may generally decline AIT screening in favor of physical screening, TSA may direct mandatory AIT screening for some passengers.
I found out about the change as I was going through security and opted out. The folks in line behind me said “I didn’t know you could do that” and a queue formed of folks opting out. They made everyone else behind me go through the scanner, saying that it was a security risk to have folks queueing to opt out. (It’s a security risk to form a queue inside a long security screening queue?) The reality is that this rule change was needed so that they could avoid the screening process grinding to a halt if everyone requests a manual screening.