Sorry, but there are some things I just don't believe. One is this concept I keep seeing here that if I don't see anyone, then no one is there, and no one can see me. I am absolutely 100% confident that that is not true.
I think it depends on context.
The pictures of the school that I've seen show that it is surrounded by large, beautiful trees that were in full foliage that day. I didn't see a single window that was not at least partially obscured by a tree.
Furthermore, the activities inside the school that day were more conducive than usual for everyone's attention to be inside the building, rather than staring out of the windows.
Yes, there would be a certain amount of risk involved but if this were a premeditated crime, the perpetrator was obviously someone who is bold and not risk averse. If this were premeditated, I'd say that the perpetrator took a calculated risk and it did succeed (so far as we know).
On another thread, someone mentioned Ted Bundy's last victim, a 12 year old named Kimberly Leach that he abducted from her school during school hours. That wasn't the only victim he abducted from a school during a school event. He abducted Debra Kent either from inside her school (a teacher placed him inside the school) or from directly outside it during an event that was attended by an estimated 1100 people.
Ted was really an expert at abducting victims from amongst dozens of potential witnesses without being noticed. The instance I found creepiest was his abduction of Georgeann Hawkins.
She disappeared walking down an alley towards the sorority house she lived in. There were other sororities and fraternities on the same alley and there were end of term parties going on at all of them. It was after dark but most of the alley was quite well lit because of the parties. There were just a few dark patches.
Her movements were traced to within 150 feet of her own sorority, when she just vanished, despite the fact that there were hundreds of people partying up and down the alley, with a lot of foot traffic between the various parties.
One second she was there, walking down the alley with lots of other people. Then after a certain point in that alley, no one ever saw her again. She vanished from the midst of hundreds of people.
LE was never able to figure out how it happened; Bundy confessed in detail to Bob Keppel as a ruse to delay/evade the death penalty.
It turns out that he'd parked his VW Bug in that alley earlier that day, in preparation for going hunting. He'd removed the passenger front seat so that he'd have enough room to stash an unconscious/dead victim. He fixed the interior lights so they would not come on when the doors opened and placed a tire iron on the ground underneath the car. When he saw an attractive girl walking down the alley during a temporary lull in the foot traffic up and down the alley, he approached her on crutches to ask for her help. He led her to his car, grabbed the tire iron and used it to knock her out. Then he opened the door, placed her on the floor on the passenger side, covered her with a blanket, got in the car and drove away.
Not one of the thousands of eyewitnesses present that night remembered a light gold VW Bug driving away during the critical period. Not one. Bundy just flicked on his headlights as usual and drove very slowly down the alley because of all the people on foot. He passed 15 different sororities and fraternities all holding parties and literally thousands of people and yet not one single person remembered his car.
There were literally hundreds of witnesses within earshot and thousands total at all the parties on that alley and someone could have come walking past his car at any second. It looks like a fairly risky way to carry out an abduction but when I think it through, it really wasn't all that high risk.
First, it was after dark. Many of Bundy's other victims were abducted in daylight, so light was not a deterrent for him. Darkness was just an added advantage. Second, there were really only a few seconds that were risky: the time between when he rendered Georgeann Hawkins unconscious and placed her body in his car. He had already prepared his car to make placing her in it as easy as possible by removing the passenger front seat. She was standing directly next to the passenger side of his car when he hit her with the tire iron, so there were just a few seconds that he was risking being seen.
Had a witness walked down the alley while he was walking with her (Georgeann Hawkins) to his car, he would have made some excuse and let her go. She probably would never have even realised she was in danger.
If Kyron's disappearance was premeditated, I think it was done by someone easily as bold as Ted Bundy. Someone who was able to figure out risks, how to minimise them and who knew how to act in ways that do not draw the attention of others.