Harry Lime, don't listen to mysterious "luckyduck2" who at first said:
“I know because I have the same card. Dept of homeland security re-issued a paper waiver about 5 years ago. I still use card to cross at buffalo and pearson airport.... Border agents know that card and will tell you how lucky you are to have that”
Which means he didn't "need" the paper, but he still went a got it, but claims to leave it at home and just uses the card. B.S!
No wonder he won't use his real name.
If you go to the border and are told you are "ok" ask for the officers card. You dona't want to book a $5000 trip to Hawaii and suddenly be told "That card is not valid".