Carry-ons play an important part of a SDOO because you can speed them through or fiddle with them to slow down depending upon the back-up at the adjacent Cancer Machine.

I have locked up everything for years, even pre-TSA. The only item of value that's exposed these days is my laptop. It's a government laptop, BTW, so a screening clerk who made off with it is about as stupid as someone stealing a government car.

Regardless of my personal measure, if I have to opt out, you can bet I always make a big deal about being able to see my stuff.