I’m at a crossroads to be honest. My dream school is UCI but I’m waitlisted to them. However I got into UCR and UCSC. Can I SIR to both?
No you can’t. Pick one that you are accepted to and SIR. However you can still accept the W/L offer at UCI. If you get off the waitlist you can ask how to switch your acceptance.
Read this
http://admission.universityofcalifornia.edu/how-to-apply/after-you-apply/admission-decisions/