Based on low heart rate and little movement I constantly get naps counted on my 955, or an incorrect fall asleep time is counted. I know this has always been an issue.
How I've gotten around it is I've gotten into the habit of moving my wrist every few minutes if I'm relaxing so the watch doesn't think I'm falling asleep.
It would be wonderful if the watch could display a prompt that says something like "no movement detected, falling asleep?" And that message would display for 5-10 minutes (or a user configurable time) with an option to dismiss it. If you dismiss it then any calculated sleep is deleted. If you don't dismiss it then after the allotted time sleep is counted.
Seems like this would be a simple feature to add. Kind of like the "still watching?" prompt on Netflix.
Since I, and probably alot of people, look at their watch often then most false sleep could be deleted. Since naps and sleep time affect training readiness probably more than anything there really needs to be a way to get around this issue other than moving your wrist.