How does PSA Grade Pen Marked Cards if No Qualifier is Requested?

[swarmee]

MK is not one they usually remove. So if PSA thinks it's an Excellent card otherwise, it would still most likely get a 5(MK) despite requesting "no qualifiers". They reserve the right to leave the qualifier on there. Normally NQ is used for things like OC or ST. A 5(MK) would count like a PSA 3 in their registry competition.
If you really don't want to get the MK qualifier, you might need to call PSA. But I've received cards back graded PSA 1(MK) before. And I've also had multiple cards with marks not get graded as MK, probably because the grader missed it somehow. The two cards I'm thinking about were fairly obvious to spot the writing or additional ink.

Q: What are “Qualifiers” and “No Grades”?
A: A “Qualifier” is a term used when an item meets all of the criteria for a particular grade but may still have one significant flaw. Depending on the severity of the flaw, we may be able to “qualify” the item for a higher grade by identifying this indiscretion on the label, for example: OC – Off Center or PD– Print Defects. You have the option of selecting “No Qualifiers” on the submission form; however, please keep in mind the card grade will be lowered depending on the severity. Moreover, there are certain qualifiers that PSA will not remove such as MK –marked and MC – miscut, for example.

https://www.psacard.com/resources/faq