Originally Posted by
Maelochs
The marks on the seat post are put their by the seat post manufacturer in order to ensure safe and proper use of the seat post. Nothing else. Seems crystal clear. Hilarious that people would argue about it, in a nauseating sort of way.
Exactly. The seat post manufacturer is responsible for the seat post. The whole system works because each component can be trusted to be safe in itself, when used properly.
Having a seat post 2mm further out than required might be OK, but what about 10mm? 50mm? You need to provide a cut-off somewhere, as short as possible to withstand the forces applied to the post at the clamp.
Of course, in this case whilst the seatpost is fitted incorrectly, the problem is almost certainly that the clamp was overtightened which damaged the post.