They won't.

In my professional experience, having needed to work with relatively unsophisticated people across many time zones, the only thing that worked consistently was "[City] time". That way people could always check 'what time is it in X now' or 'when it's X in [City], what time is it here', and get correct responses.

Descriptors like "Mountain time" are too vague, especially when there are various places that do/do not practice DST within that timezone, or there are similarly named time zones internationally. (Australia has Eastern and Central time too, for example, and in summer - which is northern hemisphere winter - they split into four different time zones due to varying DST practices.)

Trying to be overly clever and exactly specify the time zone, e.g. "MDT", leads to lots of subtle mistakes in my experience. Often people will think they know what that is, and then get it wrong. Or their calendar app will helpfully suggest MST and they'll click on it, not noticing the difference. Or they'll just scramble the letters when writing them down and wind up with "NTT time" or "AT&T time" or some such.