The Flight 93 Memorial Site has a downloadable PDF map of the winning design, which I duly downloaded. The legend at the bottom of the map specifies it is oriented North, whether true or magnetic is not stipulated. (Magnetic declination is between 6 and 9 degrees W.) Drawing a line connecting the tips of the crescent and drawing a perpendicular, you can see which which way it "opens". Using a protractor, I found the crescent opens between 230 and 240 (southwest) degrees, or taking the reciprocal, between 50 and 60 (northeast). You are invited to do this yourselves and verify the result. . . .
Then next step was to stick these coordinates into Keyhole 2 LT, and both coordinates check out. Keyhole took me to the site with the characteristic two hills and ridge pointing northeast shown in the Flight 93 Memorial winning design. (Keyhole users, tilt the map if you have trouble distinguishing the features.) The coordinates for Mecca likewise go to "Makkah" in Saudi Arabia. Both sets of coordinates seem valid.
I tried to follow the FreeRepublic poster's calculations for bearing but found them obtuse. I could never come up with an azimuth of 124.80 degrees. So I went to two sites to independently calculate the bearing from the Flight 93 crash site to Mecca. You can go to the Marine Great Circle Calculator or WhereAreWe?. Both these sites accept the coordinates of points A and B and calculate the true bearing to get from A to B. Both give a result of 55 degrees true, or its reciprocal 235. I can tell you that my jaw fell open. The bearing given by both Great Circle Calculators corresponded near enough to the measured opening of the Crescent from the PDF map. (The reader should do this for himself).
Wretchard goes on to point out that there is about 1 in 9 chance of this happening coincidentally. To me that fact that this did happen, at a memorial to victims of Islamic terrorism no less, is one hell of a coincidence.
Previous post about the memorial here.