IMO if you're not sitting up front, who cares? All this show of appreciation etiquette stuff seems pretty self-serving to me. Don't pilots feel special enough? I recently heard a story of a regional FO rushing to the near-empty cabin to reprimand a JS who didn't "check in" up front. Since when do FOs making $25/hr care about this anyway?? I thought people usually checked in with the CA..
Dumb traditions like this get people butthurt over nothing. If you get a seat in the back, even if you filled out a jumpseat form to get it, you earned that seat just the same as any passenger... Take a seat and enjoy the ride. Oh and be nice to the flight attendant