Sales girl vs. gals just out

If a gal approaches me at a store (sales girl), I'll assume she's doing so because of her job. If a gal is just "out and about", I'll assume she's just being friendly.

A flip of this I read on here that a gal (just "out a about") sometimes will ask a guy questions just to get him talking. Any truth to this? More on this, should Í assume girls in the situation are flirting with me?
Sales girl vs. gals just out
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