Such a daft thing to say. If you are told to wear a mask then you will have to. It's not very likely but stamping your foot and saying shan't is just pointless.
Well, no. Not only are there exemptions that are unpoliceable but in the unlikely event of new mask mandates, it's clear there wouldn't be real enforcement in public spaces anyway. We saw that last time when some supermarkets basically said nah, not our job. There are some situations where some people might have to, but actually most of the population won't have to most of the time if they decide against it.
Additionally, the very clear reluctance of a good chunk of the population to go along with mask laws again is a big part of the reason why they're so unlikely at this point. The more people say 'shan't' the more obvious this is. You don't have to approve of any of this to understand that it's the reality.