Latest trick by the canuck side is to hand back all of your five assorted family IDs (passport, 3 birth certs, enhanced DL) except one. They kept my wife's enhanced drivers license during a dinner visit. After turning the van upside down we went into the port of entry from the canadian side and got an "Oh, sorey eh? Here you go." from them.
Next trip, maybe a week later, I checked through what was handed back and they'd failed to hand back the same ID...my wife's. Got that one back before leaving the booth.
