Thanks to everyone for all the help. This is a great site! Yes, the engineers are smart and numerous. Its hard to stop all the engineers from coding the wrong thing. Currently, the only indicator is a servere code slow down. I would prefer a more explicit indicator - a warning or blocked access. Thus, this thread. Scanning the user code is not that useful as many engineers will include (require/use) code from libraries. So, the check difficult. Its unfortunate that the test of "defined $&" causes the slow down. I will have to try the blocking tricks.