I'm PM and I usually get these if I check in online and haven't already gotten upgraded since it's kind of useless in FC.
Be aware that if you're using Internet Explorer 9 and you have the tracking blocker feature on, you won't see the coupon when you print. Evidently it is generated with a script when the Print Boarding Pass button is clicked. The tracking blocker is stopping some cookie creation or other process that occurs and the coupon never gets generated.
Here's a suggestion for something nice to do:
if you have one of the HOOU coupons and get upgraded, see if you can pass it along to one of the service men or women who might be on the flight. Make sure you point out that it's good for snacks since they might think it's for alcoholic beverages and refuse it.
For that matter, anyone you think might could use it would be a good choice. Be nice and spread the feebies around. I've often passed it along to a friend or co-worker who's on the same flight with me and didn't get a seat up front.