A couple of things CaveMan...
The Allegro that the original poster is referring to is in Cozumel. You are referring to Playa del Carmen, which is 9 miles across the channel. Two totally different places.
Second, the tsunami had absolutely nothing to do with beaches washing away in this part of the world. In Janaury, we often have "nortes" which actually help the beaches on this side of the channel, and possibly wash some away on the Playa del Carmen side. I don't know about Playa del Carment for a fact, because I live over on the other side...but this is a suspicion. It's all about tides and winds and ocean activity...but not as far away as Thailand/Phuket, etc.