I have dealt with both ends of that spectrum; some clerks will stamp anything you ask for, or hand it to you to stamp yourself, and others guard that stamper as if it is the Holy Grail. I just depends on who you are dealing with and on what day you are there.

It's almost comical at times to watch and listen to certain counter clerks defend the stamper as a self-perceived "untouchable" instrument and others just hand it over not unlike a pen or a stapler.