Double-blind review is a "reasonable effort" standard, just like locker room etiquette. :) You shouldn't flaunt your identity or try to spot other people's.  Discretion is good.  But elaborate disguises or blindfolds would interfere with the business at hand.   So sometimes you might catch a glimpse of something private ... you're just supposed to put it out of your mind.

(just sent this to a reviewer who was worried he might know who the author was)