My point was to illustrate how the "naive" expectation of dereferencing is contradicted by the reality of how autovivification works.

Ok, that is a perfectly reasonable explanation. It might have been nice to say that in the original post, but I know how hard it can be to figure out the things people will have questions or confusion about.

I have lately been incorporating Test::More into my perlmonks posts

I like this idea. One of the reasons I like tests is they can convey a lot of information in a convenient, machine-usable little packet. They are just like the test snippets I usually end up writing, but in addition they show where my expectations are violated or upheld.