anyone notice blackjack advantage players never actually sit down

not sure if it's just me, but i've been noticing more people who clearly know the game just hovering near tables, maybe checking out the shoe, but never actually buying in. even when a seat opens up, they kinda just drift away or keep watching. some guys do it at live dealer tables too, always talking theory in chat but never dealing chips. i get keeping a low profile but what’s the point of scouting if you never play? am i missing a next-level move here or is this just nerves?