For most schools, GPA is the first litmus test.
I’m not following how you’re deriving that and what it means. I know the OP is looking at Civil, but if there are 500+ “more stringent” ME programs than those that are ABET accredited, maybe you can list 10 of them.
ABET is not the be all, end all. It is bureaucratic and restrictive. It’s also not particularly germane to CS, unless you want to work in certain sectors. That said, the few who opt out are the bluest of blue blood names, and they generally cite good reasons. Having a non-ABET accredited degree from Caltech isn’t the same as one from Podunk U.