[blipmusic]

Using the official, graphical installer for Python 3 on Windows with no previous version installed creates an executable 'python' that refers to Python 3.

(Normally not a Windows user so I have no idea why this is the case or if by design.)

[groovy2shoes]

Windows doesn't support shebang lines, so the exact name/location of the interpreter doesn't matter as much as it does on 'nix.

[maxerickson]

Recent versions of python ship with a launcher shim for windows that does support the shebang line (to simplify using multiple interpreters):

https://www.python.org/dev/peps/pep-0397/

As you say though, it doesn't rely on the names of the exes.