[bhaak]

You are technically correct.

In reality though you can't expect programmers to code for eventualities that occur only in extremely rare cases (until now).

[underyx]

It's less rare than you think. Lots of repos use "develop", or "trunk" as their default, for instance.

[bhaak]

Yes, many repositories use something else than "master" as their main development branch.

But how many of those don't have a "master" branch at all?