I have to say that I disagree with you here
chip - The concept that the language designers should limit an interface to shield even only potentially unfriendly arguments, particularly where such arguments may be perfectly valid (as described by
merlyn above), is in itself flawed. Perl has always been described as "providing enough rope to hang yourself with" - I would much rather take those steps of good engineering than sacrifice any power within the underlying language interface.
perl -e 's&&rob@cowsnet.com.au&&&split/[@.]/&&s&.com.&_&&&print'