Can I send a Letter of Continued Interest to UCSD?

On the UCSD waitlist FAQ they say:
Q: Can I send letters of recommendation or other documents? A: No. Additional materials (including letters of recommendation) cannot be accepted. If you do send them, they will not be reviewed.

Does this include letters to express why you want to attend? I was reading some articles on what to do when waitlisted and saw many suggestions to write such a letter of continued interest.

Thanks so much!

If UCSD wanted additional materials to be sent for their waitlist review, they would have stated so when you opted in. UCSD does not consider an applicant’s level of interest according to their common dataset.

http://studentresearch.ucsd.edu/_files/stats-data/common-data-set/c.pdf