A good friend of mine went to Brown undergrad for pre-med and he said that med schools wanted to know his grade in every class, so he really couldn’t use the p/f option as I think you’re implying. If you decide not to pursue pre-med, sure you can use that flexibility at Brown. BTW, I think most colleges allow dropping without it appearing as a W on the transcript, within the first couple of weeks but maybe changing from graded to P/NC is easier to do at Brown as is the test driving option.
“Don’t confuse freedom in the curriculum with lack of rigor.”
When I was applying in the mid- 80s Brown was known for being open an not having grades and was very popular for those reasons! But agree, I looked at Brown’s engineering curriculum for an older thread on c/c and the first two years at Brown are pretty much required core classes in addition to four humanities classes being required over the four years.