[cm2012]

In NYC, at least, in 100s of places, I've literally never seen someone check a $20 in any way other than putting it up to the light, and that is 5% of the time. I'm sure it happens though.

[justin66]

I never noticed it in San Francisco or the East Bay, but I lived there a fairly long time ago. In the midwest, I see it often. Not sure what that's about.

[mpyne]

When I was a cashier way back in the day (around the turn of the century) we checked $20s and higher with the marker pen thingy.