In response to a March 2002 review, yes, my tailgate has opened on its own several times. The trick is to close it firmly & try to open before you move. If its tight, it will stay closed. If not, it will sound like you ran over something when it drops opens!
I had a problem with water leaks in the 3-piece bed cover. The seals did not appear to be attached well & water sometimes poured in. Per the dealer, the seals are not factory installed, but are installed at some later time. To correct, the dealer first tried to reseat the seals. This wasn't a complete fix, so they borrowed a cover off another truck & I've had no problems since.
I traded a 2002 Acura TL Type S because I needed more room (new baby!). This rides better than my Acura. Truck is full of neat ideas, like steps built into the bumper & side bins that double as a cooler. Sheer mass (in an accident, 5800+-lbs should beat just about anything). Onstar works!