Walking bikes across streets?!?

I know it’s not the profoundly incisive commentary I had envisioned for my first thread but what the heck!
On my commute, I pass at least 5 or 6 elementary schools. Twice in the last week I have seen a kid riding down the sidewalk only to try a hurried dismount at the crosswalk and crash. The one this morning cost the poor guy a tooth! I had to stop to help him as he lay there till the moron crossing guard figured to send for some help. ( but that’s a topic for another day).
The kid told me, and was verified by the guard that you must walk across a crosswalk, even if there is no other pedestrian traffic! Maybe it’s because I have ridden for most of my life, but I can’t think of one good reason for this.
The obvious is that kids aren’t skilled enough to manage a crosswalk, but I don’t buy it. Any thoughts>?

Under the road rules (in Pittsburgh, anyway) if you were ON the bike, then you were a vehicle and subject to the same laws as cars. If you were walking the bike, you were a pedestrian, and enjoyed the rights/protections of being a pedestrian. I often hopped off to cross a particularly busy street.

I am not sure how this relates to the elementary school kids in your situation, but this might be the reason they are supposed to walk the bike across.

Perhaps the rule got started because it’s easier to drop the bike and dodge the moronic driver who doesn’t stop at the crosswalk on foot than it is to either try and ride out of his way or jump off the bike and dodge.