Is it normal for my gf to feel flattered when other guys hits on her?

My gf is attractive, so she gets hit on a bit. So she was telling me about this guy at work trying to hit on her and I am thankful she lets me know. I like open relationships. However I asked her if she gets flattered when she gets hit on by the guy and shes like well yeah everyone gets flattered. She has not really mention me to the guy, and its not the first time the guy keeps persisting. She said she feels rude telling him that she is in a relationship until he takes a more aggressive step.

Just wanted to know if most of you women out there think the same?