If it is one of those tickets that cuts of a "stub" every time you use it, I would send it in and write a letter of complaint. They may still argue that you should have checked how many times it has been actually stamped but at least they will get an "eye-opener" for a potential problem with their machines/system.

Had it been in Zürich, you may even had gotten an appology as we have seen examples of here on the forum recently.