It's not "just" those who haven't been vaccinated at risk, though - vaccines often have both an efficacy rate (the likelihood you develop sufficient immune resp

It's not "just" those who haven't been vaccinated at risk, though - vaccines often have both an efficacy rate (the likelihood you develop sufficient immune response) and duration (how long it lasts without repetition). One of my relatives was vaccinated for pertussis, and yet still came down with it one day. Their parent had a hard time convincing the doctors to even test for it because, in their minds, it was no longer an option. Even later, it came out that the particular vaccine that my relative had been given had a markedly lower effective duration than had been initially advertised. So even if other entities make all the "safe" choices (presuming they're not immunocompromised or otherwise unable to be vaccinated), disruptions in herd immunity can have problematic consequences.