I was under the impression that "overloading", as you put it, was purely a function of the CGI module, that the html would just send a bunch of foo=bar;foo=baz;foo=qux in the querystatement then the module would handle collapsing it?

You are correct - the actual HTTP submission by the browser will contain the repeated entries even for text inputs and the like. I wouldn't recommend relying on that, though, because it forces you to handle bottom-up form processing (including handling the URL encoding and crap like that). Even if you don't mind today, you'll be in a hole when you decide to just use CGI.pm or whatever tomorrow because it has that one added feature you'd like.

I speak as someone who once tried to save some time doing this and found it wasn't worth it in the end 8)