Most of my employers have had the attitude "Do whatever you like, but it's your $#%@ if it breaks." I personally have never run into a similar policy.
in reply to Production Environments and "Foreign" Code
As for modules ... my feeling is that the "core" modules are a subset of the real "core" modules. I have never had a problem d/l'ing almost any CPAN module and having it work according to docs. (This doesn't mean that I didn't have to extensively augment/modify the module(s), but that's another story.) No data loss, no corruption, no nothing. YMMV.
We are the carpenters and bricklayers of the Information Age.
Don't go borrowing trouble. For programmers, this means Worry only about what you need to implement.
Please remember that I'm crufty and crochety. All opinions are purely mine and all code is untested, unless otherwise specified.