Far be it from me to discourage the use of warnings and strict. It's extremely disheartening to read in one of the responses from LanX that someone was ever fired for using them.

As you've pointed out, one aspect of this that I've found useful resorted to in very rare cases was to switch off warnings in only a certain part of a program in an enclosing block. This was almost always because of the "uninitialized" warning sounding off when it was irrelevant. I recall reading some CPAN code recently where the "once" warning was bothering a certain Matt Trout. (See the colorful language on line 95 of Moo.pm v 1.000007)

As for me, I can't think of a time when it would ever be apropos to disable strict or warnings completely.