I'm not sure if I agree with you about putting the code into UNIVERSAL. Anyway, looks quite logical since is the kind of function that any superclass should use. Why do you think is not a good idea?

Regarding the exception during compilation time, this would kill any module that generates code during execution time. Since we're talking about Perl after all, this is really a bad thing to do and I don't think is worth to do it to just receive a die because the programmer forgot to override a method.