Because unless should only ever be used as a statement modifier: 

    die "Tough beans.\n"
        unless  isValidUser();

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Otherwise it just makes your code harder to maintain and some find it confusing (even many who don't realize that they find it confusing). While, as a statement modifier, it can make some code read more naturally.

        - tye (I'm exactly half serious)

In reply to (tye)Re: if/unless and chaining by tye
in thread if/unless and chaining by John M. Dlugosz

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