"Public" wifi certificate and encryption

I have a question- if someone is on a so-called public wifi (like an airport, university, etc), and the network requires them to agree to terms and conditions, then installs a certificate, does that mean that any VP N used is useless? To clarify, what I'm asking is not "why would the university spy on you?"; What I'm asking is - can wifi certificate undo/bypass VP N encryption?

airport asking called certificate conditions encryption etc network privacy public public wifi question spy terms university useless wifi