I think that would be the expectation of most non-engineers, assuming they set the new time zone before arriving and if they even considered edge cases like that. It's also how most alarms work, whether mechanical or digital.
The code is not strictly public domain: it is copyright
CERN (see copyright notice is in the .tar), but is free
to collaborating institutes.
Was it typical back then to release code while retaining the copyright as opposed to making it public domain?