Does not use -w or strict. These are great for development. But if it could compile under -w and strict, and produce no warnings or halts, then it is safe to take them out right?

I would have to disagree with that. It's true that -w and use strict provide useful checks at compile time, but they also operate at run time. strict 'refs', which prevents the use of symbolic references, only works at run time. Warnings that occur at run time include 'Use of uninitialized value', 'Filehandle opened only for input', and 'Exiting subroutine via next'.

So, if your program compiles without error or warning, that's great, but there may still be bugs that -w and use strict can only report while the program is running.