What would people think of a man wearing 4 inch heels?

you gonna pay them to wear them?

I've already seen that in an avant garde performance during my university days. The man was also in a womans slip. I couldn't care less if I see that again...

I'm thinking possible Brooklyn hipster or some similar 'Look at me! Look at me! Why doesn't someone pay attention to me?!' ego-monster....

I would think he was taller by 4 inches.

you got a time machine or something?

sounds like we're going back to the 70's

I would be (reluctantly) impressed, if he could actually walk in them!
I never quite managed it, say nothing of in considerably lower heels. Gave up trying pretty quickly.
I would also be concerned about long-term harm to his feet & back, if he wore them a lot.

He couldn't find any 5 inch heels.

I gave the idea a second thought. He could be a really unambitious stilt walker.