I went to Clearwater Beach today (I usually skip that and go to Caladesi). Whilst there I saw 100+ Laughing Gulls, 100+ Sandwich Terns (2x Forster’s, 13x Royals) 25+ Sanderlings, a smattering of other species (5x Pelicans, 2x Cormorants, 1x Willet, 3x Turnstones, etc) and 6 Red Knots. I noticed the Knots had “leg-rings” (I think you call them “leg bands” here) but also they had (what I learned through an hour’s Googling to be called) “leg flags with codes”. Here are a couple of pictures of the bands / flags. Apparantly, the numbers, letters, colours and leg positions (upper, lower, left & right) mean they can be individually identified. The alphanumeric codes are clearly visible as “TV6” and “89X”. The green colour signifies they were banded in the USA (in NJ if I understand correctly).