My daughter was diagnosed with absence seizures, but what alerted the teacher was the staring and seeming to be out of it, and failure to comply with simple requests and confusion about the requests. At first we thought it would be ADD, but it turns out it was epilepsy.
There would be no reason to go to the ER for simple absence seizures. Most children outgrow them (my daughter has, thankfully) and she has thus far navigated adolescence without any seizure activity reoccurring, thank goodness.
Just as an FYI, one simple diagnostic tool is to have the child mildly hyperventilate and see if it occurs. My pediatrician used a pinwheel, and encouraged my daughter to keep blowing it, and then her staring spell came on. They did the same thing during her brain scan, and the neurologist said she was textbook.
About 20% of children with absence seizures will, once medicated for them, develop another, more severe form of seizure activity. My daughter had a few of those episodes while the neurologist was tweaking her medications.
Not that I am suggesting that anything like this happened to Kyron, but it does make me go "Hmmm."