If you intend to try to j/s on AC for flights into the US, that shouldn't be a big deal. Just make sure you list yourself ahead of time, cuz those ticket counters don't know much about JS.
If you try to j/s int'l in Canada, i won't say it's the same. I had to burn a pass on my last try when I j/s out of YYZ into europe. I wasn't given a reason...