Without a doubt. I've envisioned this hypothetical dialog many times:

phb: You checked in a module from CPAN.
dev: Yeah it does everything we need!
phb: You'll have to delete that, we can't use modules.
dev: So how am I supposed to do it?
phb: I dunno, go ask on perlmonks!
[download]

But if you know app dev you can avoid those situations way before it happens. I'm aware that many people aren't this fortunate though.