Why Do People Queue for Hours at The Row’s Sample Sale?

The Row’s annual sample sale, where Olsen acolytes can score rare discounts of up to 75 percent on the label’s shoes, coats and blazers, has always gotten fashionable New Yorkers’ blood pumping.

But in recent years the sale has gone from an “if you know, you know” event to a collective mania — with lines around the block warranting coverage from Vogue and The Daily Mail.

Starting Tuesday, the night before the sale opened, tents — many housing paid line sitters dispatched by the…