I will analyze this critically by noting how many men enter the store, how close they get to the fitting rooms, and if marital status affects whether or not it's acceptable for a couple to share a fitting room. With that, I will go to the store with my parents and my boyfriend to see how my parents are treated and how I am treated. (Hoping my dad doesn't flipping the F*** out!).
Maybe answers will be different depending on the store and their reputations. Victoria's Secret is known for being more sophisticated and classy rather than Frederick's of Hollywood where their attire is much more risqué than Victoria's Secret. For example, Frederick's sells edible underwear where Victoria's Secret doesn't provide such exotic attire. So I hope I do find different answers to provide and present.