The reason I'm annoyed, and the reason their short-term benefit of advertising has backfired, is because the pen covered my desk in gunk. It's a good pen now, after I removed the logo and hence the remaining source of gunk, but until then it was a liability.

If the pint-to-line mark had rubbed off in such a way as to noticeably pollute the beer, that would have been an analogous case.

I believe legally-required markings on a glass (pint/half lines, crown mark) have to be etched, and only decorative designs can be printed. And presumably on the outside.

The ipnt and half pint lines on all my CAMRA pint glasses are externally printed, I think.

I remember getting a glass at a beer restival whose (external) pint marker rubbed off unpleasantly.