Levity aside, having lived in Saudi, the only thing that is surprising about this is that it occurred in a Mosque. By law, all Mosques are required to have the correct direction of prayer "built in", and therefore pretty much idiot proof. So someone screwed up during the planning and construction of this particular Mosque.
As a general rule, especially in the hinderlands, when the call to prayer comes, I nave seen Saudis throw their prayer rugs down in virtually any convenient direction, for a couple of reasons. First, depending on where you happen to be in Saudi, Mecca can be on any point of the compass, and second, Saudis, on average, are an ignorant lot, and figuring out the correct direction for most of them is simply a "bridge too far"......
When not in a Mosque, Islam charges the believer to pray in private when possible, however in the cities, virtually every building with public access has a compass rose embedded in the mosaic on the floor indicating the proper direction (and "prayer rooms" are provided)......even the public parks.
The "Religious Police", or Mutaween (which are found EVERYWHERE), when I was there, all carried a compass and a map to advise believers the proper direction........I suspect that these have now been replaced by hand-held GPS receivers.
doc