Well apparently someone forgot. snapped this from the abc news website today. It's from the popes arrival at the white house. saw it like 30 seconds after first reading this thread.
And according to wikipedia (for what it's worth) George is methodist, so I'm assuming Laura is too. And the queen is defiantly not catholic. Why should they follow catholic rules.
So maybe it has to do with where they are meeting. Maybe they wear black out of respect if they are at the Vatican. I by no means am into organized religion, but i still took my hat off when in Notre Dame, Since i was on "their turf"
And one of my now all-time favorite graphics from the daily show last night. Since George went to the airport to meet the pope. Which apparently is very out of the ordinary for any president to do. First time he has ever done it. and the first time for any president at Andrews Air Force Base.