Where we live, if you don't kite alone sometimes, you won't kite very often. My rule of thumb is that I won't kite by myself unless there are other eyes on me. They might be boaters, folks along shore, ice fishermen, etc. In Tom's case, I would alaso have gone out. He checked with the ice fishermen, and they said there was 8 inches of ice. That sounds like plenty to me. There were ice fishermen there, just not in the immediate vicinity of where he went through the ice. At the spot he went through, the guys were too far away from him to hear him shouting, and had their backs to him and didn't see him. I suspect that there were some folks on shore that may have noticed him, but not that he had gone through the ice. The launch site is on a main drag of a small town, and there are restaurants across the street from the lake and the windows face the lake. I suspect Tom was too far away for them to clearly see that he had gone through the ice. He also made it back out onto the ice pretty quickly (sounds like less than 5 minutes), so no alarm was sounded. I'll bet that if he had been stuck in the water very long, folks would have alerted the authorities pretty quickly.
As an example, when I was kiting on Lake Michigan (no other kiters) in March a few years ago, the wind was super light and my kite came down. It took about a half-hour of dangling in the water before the wind picked up enough for me to relaunch. I was only about 200 yards from shore, but quite comfortable so I didn't wrap up and swim in. By the time I had relaunched the kite, the EMT guys were headed for me because "several" calls had been made believing I was in trouble. I was a bit embarrassed, but glad that folks on shore had made the calls when they saw somebody that they thought was in trouble.
So the "don't kite alone" admonishment is a good one, but "alone" doesn't necessarily mean "a lone kiter". However, there is a lake nearby where I won't kite unless there's another kiter with me, because at that location I would likely be truly "alone".