ChemBoy mentioned that this didn't work for him so I tested with Perl 5.004_01 and got an empty array and no error message (though subsequent <>s resumed where they had left off). ChemBoy seems to get different results from either of my tests.

So perhaps this overly-cute hack works for 5.6 but fails in different ways for earlier versions. More data is required before I'd draw any firm conclusions, but at least isn't just my word against ChemBoy's now.