What's the courtesy: wipe off the wash basin?

Commercial airliners often have a sign in the bathroom that reads:

As a courtesy to the next passenger may we suggest that you use your towel to wipe off the wash basin

I've never really figured it out.

I have never felt disrespected by water left over in the wash basin by the person before me.

What's the deal?

Best Answer

I have always felt that it is a subtle way of saying:

"If you sprinkle when you tinkle, be a sweet and wipe the seat"

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