Is an eyebrow flash a sign of attraction?

[Dunno1998]

So basically I'm a cashier, and whenever guys come up to my register they will usually smile at me and do an 'eyebrow flash' (usually guys around my age, older men don't do it as often) and most women don't bother with an 'eyebrow flash' either but will smile at me.

So I read somewhere that this eyebrow flash is a sign of attraction, but maybe it's just something people do when greeting someone?

[LaVilaine]

I don't think it's a sign of interest. I think it's a non-verbal greeting.

[darksciences]

Greeting someone! No flirting ma'am!