@ZipLine-- I don't think that someone who doesn't know the individual and their health background would be able to tell apart a diabetic seizure and an epilepsy seizure. You are right in that they look very similar. I guess the only way to know would be to check the person's blood sugar before the seizure takes place which isn't possible in an emergency.
Both diabetic and epileptic seizures show the same signs. There can be loss of awareness or consciousness, convulsions, confusion, difficulty speaking and swallowing, shaking and eyes can be rolled back.
Regardless of what the seizure may be, bystanders should call 911 and let the medical professionals take care of it.