A certain US model would do just that.

Like almost all carbon bikes, the seat tube ended a cm or two above the top tube, and it had no collar, but a molded-in binder. It had an aluminum "sleeve" inside the seat tube that went down about 2". The cavity of the seat tube itself bottomed out about 6" down.

The design called for the seat post to be cut perfectly, and inserted all the way to where it stopped at the bottom of the seat tube cavity. Unwittingly, riders would raise the seat post and leave a gap between the bottom of the seat tube and the bottom of the seat post.

Once the seat post was raised enough, the seat post and saddle had considerable "leverage" if acted upon by forces, especially from the side. Often enough, the bike would fall over, the saddle would hit the ground, and that leverage would cause the top of the seat tube to be cracked. I've seen the aluminum sleeve crack completely through and still be held in place by the adhesive inside the carbon seat tube. I've also seen it happen on the models with aero seat posts that are a lot beefier, but the seat tube on those has no aluminum sleeve.

I've fixed two of them like that, though the manufacturer told me "it's possible, but not recommended." I pulled out the sleeve remnants, cleaned and prepped the area with some stuff used in windshield replacement, and then used a glue supplied by a windshield replacement firm to reset the sleeve in place. Once it set, I had to hone out the residue, and it was like new, probably stronger than when new.

Every I've worked on one of these models, I've told the owner to get a new seat post, and cut it to reach the bottom. Not one has done it, but at least they were informed.

I also saw this happen to a Schwinn 564 that the owner had configured with the quill seat post out to the minimum insertion line. It fell over, the saddle hit the ground, and it cracked the seat tube above the top tube.