Well isn't that special....

[EightFingers]

Cleaning windows on my house and noticed the bathroom vent fan cover on the outside was a little brittle. I snapped off the little shutter-like things and discovered that the wood was solid behind it. There was no hole for the bathroom fan to exhaust outside! The cover was purely "decorative".
So now I'm going to have to tear into the ceiling and see what is going on up there and run the ductwork properly [!][!]

My advice is keep an eye on your builders and assume everything is suspect.