I can't say I've ever flat out missed a flight, if you as an SE did, I think they'd be more willing to help you out, but randoms, and on award tickets, you're asking for a disastrous maze of phone calls. Call AC, they say call AP, they say talk to the desk...it's just not something you want.

It also depends on the airlines, the legacy carriers, much like with oversized bags are way more anal about stuff like this. Whereas you no show a Westjet flight and you might very well get a "awww that sucks, here let me book you on the next flight" and like a $50 fee rather than $200 + the fare difference or whatever.

I just remembered, I actually recently missed an award flight. PIT-YYZ, got drunk at the hockey game, and the peeler bar, overslept on a cloud of a bed. Realized what happened, called the AP SE line because it would've been my first flight as SE and she rebooked me right away. Now, that said, the next flight of the day was also wide open. Plus it was just that, no connections or anything. I could've sworn she said it was gonna be $101, but then the only bill I ever got was $1.

Point being, if it were just you, I'd say chance it, but a big party like this all on awards etc etc etc, it's just not worth the risk.