When I go to Las Vegas, I like to play a game called "Spot the Hooker" with my friends. People who haven't been there sometimes think prostitution is legal in Vegas, but it's not, just in Nevada. There are a lot of sex workers plying their trade in the casinos though, and these indicators would apply to them as well since they want to meet guys. If you're not in Sin City, these signs only apply IN A BAR. Just because a woman smiles at you on the street, at a coffee shop, or in a supermarket doesn't mean shit. She might just be a nice person.