99.9% of the time, on domestic flights, you will find me seated in first in 1A. That's my seat. ^

I sit there for three reasons:

A. I love flying in first;
B. I don't like people flopping their seats back into my lap; and
C. I like to put my feet on the bulkhead.

I can't imagine any reason on earth how this could affect someone sitting behind me. I always wear socks on the plane and cover my feet with a blanket. If this causes you a problem, then I guess you will just have to learn to deal with it.

Because of my proximity to the galley, an probably my advanced age, I usually end up making friends with the first-class crew. They have never expressed a concern about my feet on the bulkhead, as they quite regularly refill my wine glass. Why would anyone else care?

Having said that, I was a little put off last week when I noticed a bare foot sneaking onto my armrest on a one-class CRJ. That, IMHO, constituted encroachment. As I was re-arranging my pillows, seat, magazine, book, etc., I accidentally smacked the encroaching toe with the corner of my magazine. The foot disappeared, never to return.

I must admit that I found the "accidentally spilling water" solution suggested above is equally interesting.

FWIW, I recently had a massage thereapist comment on how healthy, beautiful and clean my feet were for a woman of my age. Whatever that means.