This is a quite solid concept. Especially regarding MBA's there's a lot of people management concepts where you can't really get the proper context without having seen in practice the environment in which they'd be applied, and you can't get that environment in a classroom. There are professional MBA programs which require a few years of work experience to join, and it makes quite a difference IMHO.

I'm not that certain about CS. If you're doing software engineering (or research on 'meta-SE' e.g. methodology, architecture, programming languages), then yes, it'd make all sense to get some industry experience between college and masters; however if you're going to grad school for theoretical CS or machine learning or cryptography or quantum algorithms or any other directions of primarily academic research, then industry experience is helpful but definitely isn't necessary.