In the case of petit mal seizures or absence seizures the person is simply not aware of the outside world. The conscious part of their brain 
is “turned off”. It may look like the person is daydreaming, but this can also happen while the person is walking or taking out the trash or eating. They would do these things automatically and be fully unaware of their surroundings.
It surely helps to know the person well to establish if the person is daydreaming or there is a bigger problem.
Additionally, when daydreaming, it is very much possible to catch the person’s attention by snapping fingers or calling out to them and, as a result, the person would re-focus and react accordingly.
When a person is having petit mal seizures or absence seizures this would be impossible to do – you would simply get no reaction whatsoever from the person even if you wave hands in their face and scream loud.
This post is very useful for me, much appreciated! 🙂
Still I find it is nearly impossible for most people to tell the difference between petit mal seizures and day dreaming
a lot of people daydream in class, now we have to ask everyone if they have petit mal?