The article below is for the most part accurate. If a foreigner is waied by a Thai this is considered a great respect. The higher the wai the greater the respect.
A western wai will not go past the nose as that is saved for Thai elders, mothers, fathers and greater. If the wai goes up the face and across the head near the back of the head he or she is Thai royalty.
If you are waied and called con (pronounced coon) Patrick, man your are in the "in crowd" and did something right along your travels. This is the ultimate sign of respect and something to take very seriously. It's a really humbling experience to be waied and even more humbling to be called, "Con Patrick".