Dear Miss Manners:
I carry a big black umbrella, even if there's just a thirty percent chance of
rain.  May I ask a young lady who is a stranger to me to share its protection?
This morning, I was waiting for a bus in comparative comfort, my umbrella
protecting me from the downpour, and noticed an attractive young woman getting
soaked.  I have often seen her at my bus stop, although we have never spoken,
and I don't even know her name.  Could I have asked her to get under my
umbrella without seeming insulting?

Gentle Reader:
Certainly.  Consideration for those less fortunate than you is always proper,
although it would be more convincing if you stopped babbling about how
attractive she is.  In order not to give Good Samaritanism a bad name, Miss
Manners asks you to allow her two or three rainy days of unmolested protection
before making your attack.