This happened to me.
Last week I was at a music store with my friend and this employee stopped and stared at me and gave me this weird look. I was already walking towards his direction so I tell him 'what's wrong?' He shook his head and literally walked away with his face down. Is this what it was?
But to answer your question, no. When I see someone hot/cute I don't do anything. Basically I'm probably on my phone, so I continue using my phone.