McMurdo is a special case of a more general problem, which is the representation of locations while uninhabited. *Every* location in the tz database was uninhabited at *some* point, and the tz database does not attempt to systematically record the details of when a location was inhabited and when it wasn't, as that's outside the scope (and the values are typically unknown anyway). In practice I've used "zzz" entries for uninhabited locations only when the database format *forced* a value. When it doesn't force a value I haven't worried about it, and I'd rather not start worrying about it now. There's an amusing instance of the opposite problem in Pacific/Johnston, which was inhabited when we created the tz database but became uninhabited in 2004. Its entry cheerily says "We're just like Honolulu!", and really, that's OK: worrying about the discrepancy would be more trouble for everybody than it's worth.