I have been on a BiPAP since Fall of 2004. I still do this occasionally. It may sound awful but if I don't wear it for a night, after taking it off for several nights, I can sleep a full night with it on.
Also, my machine was originally set to turn off after not being used for 10 seconds. I had that readjusted so it keeps blowing until I either turn off the machine or put the mask back on. The technichian where I take my machine said that my machine also has a setting so it beeps when its not used for the 10 seconds.
I hope that helps.