For heavy sleepers it's bad.
People who don't wake up even if there was a thunderstorm outside, like me.
For more shallow sleepers it's okay, but there's still a bigger chance to wake up in the middle of the night instead of early.
and there's still the chance that you're too tired to go to the toilet and instead wet your bed.
Too risky. Then again, I have only "tried" it once.
I have like 20 alarms on my iPhone, each 5 minutes apart from each other.
My Dad just walks in and rips the blanket of me, I slept naked once... Never doing it again.