In my code _set methods are always called with key => value pairs. Silently assigning undef is actually a bug, but (I said that code had not been tested) could be fixed by adding die "unbalanced assignment group: ".join(', ', @_) if @_ & 1; which is also a bit more messy.

I personally believe that no warnings (along with no strict) should be syntax-highlighted in bright bold primary red and generally avoided. There are a few times I have had to write no strict, usually when doing some types of meta-programming, but it is very rare in my code. I am not sure if I have ever written no warnings.