Is it impolite to refuse to share your umbrella with a stranger when it's raining?

[jali]

You said this yesterday:

@Annie-Xmas

Absolutely nobody better drop by me unannounced. They will not be let in unless it’s a dire emergency. I didn’t even call my best friend when I was in a bus accident two blocks from her house.

Your friends can’t invade your space, but you feel that a stranger should allow you access to their space because it’s raining.