Admission by Major?

Does UC Davis Engineering admit by major like UCB does? (i.e., if I apply as a MechE major and want to switch to CSE later, will that pose a problem for me? I’m pretty undecided between the two, but applying as a MechE major will be more advantageous for me because I have more extracurriculars related to it.)

Also, if someone could let me know the same thing about UCSD, that would be incredibly helpful.

For Engineering, UCD admits by major but switching within the Engineering department should not be a problem.

UCSD admits into the University first and then into the major. All Engineering majors are capped (impacted) at UCSD so switching within the same department SHOULD BE EASIER than switching from a non-Engineering/Undecided to an Engineering major. If you are applying to UCSD for ME, select a non-capped major as an alternate. If you are admitted but not into your major and you do not select an alternate, then you be placed in Undeclared and it is extremely difficult to switch into an Engineering major later.

http://cse.ucsd.edu/CappedMajor

If you are applying to UCSB and do not select an alternate major, the same issue of being accepted as Undeclared could also happen.