Just to throw in another side note :-)

And we had recently a discussion about people complaining that undefined values raise far too many warnings. ;-)

Even here, I think giving the programmer control is the best option: When I'm generating stuff from templates, I often use no warnings 'uninitialized'; because I want my undefs to silently become "", but when I'm handling other data, e.g. from a database where there is a difference between NULL and 0.0, I prefer having the warnings (and once in a while I may even fatalize them).