That's something I learned not to do when I was four years old. BIG NO NO with my Mom. Last night, we were in a BBQ Restaurant and some "grown" man was sitting in a booth with his feet propped on the seat across from him. Airports are REALLY bad. When we were in O Hare a couple of months ago, we saw AA lady, fresh from the Bathroom, put her feet on a chair. Used to be a thing you'd see every now n then. Usually young people. But now, it's "Adults".