I obviously got the date wrong for this trip report - 4/12/09 it should have been, but that hasn't bothered anyone, obviously.
I don't know how I forgot this, but I remembered this morning. There was a very entertaining group of about 6 people dressed in "easter costume" - silk and taffeta frilly dresses in bright colors - red, pink, green. They looked fantastic. Both the men and the women were dressed this way
Suggestion: Formal attire, at least for the hike, would not be inappropriate. Colors that stand out from the surrounding geography, even better.