Last time I was able to do that was in 2005 on OS returning from VIE to YUL, somewhere above Tadoussac. As a non-North American carrier, it remains pilot's discretion.

Of course, the late-evening flight YYZ-YUL all in the jumpseat of a 330 in August 2001 was very memorable (top of descent is at Kingston, and you can already see the lights of Montreal!) as was the same experience BOS-YUL a few years earlier in a CRJ. Oh well... no more of that, unfortunately.