Is attrition from engineering partly due to admission-to-major barriers?

At Cal Poly’s big rival down the road (UCSB), they do somewhere in between UW and CP. First year MEs do Matlab programming, Solidworks design with some hands on building, plus an optional machine shop course and a 1 unit overview. 2nd year is 5 required ME courses plus 1 optional. So up to 9 ME courses the first 2 years + an engineering programming course. The design course apparently changed this year to be more hands on.

Re: http://talk.collegeconfidential.com/university-california-san-diego/1881773-this-quarter-you-needed-a-4-0-to-transfer-into-cs-at-ucsd.html

If true, then UCSD becomes a very risky option for an intended CS major who did not get direct admission to the major.