Maybe...but a lot of the posts on here seem to validate my claim. A lot of people admit to being tired, and falling asleep in movies that they were actually enjoying.
I have done it myself, struggled to stay awake in cinemas when I was really enjoying the movie. And at home too.
The 'film was so boring it sent me to sleep' claim is really a stupid old myth - you fall asleep because you are tired, end of.