I'm not sure I really agree with this. While most of my applications are for internal customers (and so I don't worry too much about the point tilly raised), it seems to me that if you have a lot of warning chaff in your logs, the solution is to fix the warnings, not suppress them. I generally leave CGI::Carp directives like 'FatalsToBrowser' in effect for my web apps -- I'd much rather my internal customers get an intelligible error message than something less helpful, if only so that when they e-mail me about it, I can start thinking about the cause of the problem immediately (without sifting through the logs). I think it also helps my customers to see that when errors happen, they're for a reason (and sometimes are because of other dependent systems, and therefore not entirely my fault). :)
Of course, OfficeLinebacker may have been talking more about suppressing debug stuff, which can be configured nicely with things like Log::Log4perl.