On the other hand, the current behavior may be somewhat entrenched, and might break our promise to assume that code is Perl 5 until we see a different indication. As an alternative, perhaps the -H command-line switch could be used to use a "hello world" program.
I think we need to consider all of the implications here: "Hello World" is very english centric, so I would assume that Perl 6 would need investigate the locale and change the text to "Monde, Allo!" if you're using a French locale, "Hallo, Welt!" for German locale, and "1 april!" for Dutch. ;-)
Liz