X5 owners should check their rear bumper
Thanks for the replies everyone. I found another X5 on the street with the same problem. I think this is very wide spread, and the comments from the dealer suggest so. Unless you open the bottom rear tailgate, you might not notice it. Then you try to open the lower rear tailgate and it rubs the paint job, and you realize the bumper is loose. I'll probably put a card on the guys BWM who parks in our garage.
We are currently fighting with the dealership on this now. Also have put a call into BMW customer service. The dealership has agreed to fix this second time for free but we want the last $500 back and coverage for the future as well.
The suggestions on the Bumper Law got me looking and I also noticed that NY State has a bumper quality law where a sticker is supposed to be attached and certify the quality of the bumper (looks like it was put in place because consumers were getting gouged for bumper repairs). The combination of the national and state law basically say, a bumper is for bumping into and it shouldn't leave a mess or fall off if done at low speed. It even mentions clips.
If you own an X5 with the black plastic rear bumper, check the top of it just under the tailgate and make sure it isn't wrinkled or loose. You will have a real serious problem if it falls off as then the costs run into the $1000's. And post your problems here.