The requisite one urinal minimum you put between you and any other men who may be pissing at a row of urinals. It's a courtesy thing, and it's about proximity more than line of sight: shame shields don't obviate the need for a buffer urinal.

Of course, when you're in a situation where the buffer is impossible because there are more men than there are urinals (sporting events, concerts, etc.), the buffer urinal no longer applies.
I took my place in the row, making sure to leave a buffer urinal between me and the blonde.
by The Grammar Nazi March 20, 2004
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