BTW, is 'return 3;' a statement? If so, is it then a special exception to the rule 'blocks return the value of the last statement executed', or is the value of 'return 3' equal to 3 ?

No exception. That's indeed what a block returns, and the same goes for subs. They return the the value of the last statement executed.

sub foo {
   if (0) {       # <- Last statement executed
      1
   }
}                 # Foo returned 0.
[download]

sub foo {
   if (2) {
      3           # <- Last statement executed
   }
}                 # Foo returned 3.
[download]

sub foo {
   return 4;      # <- Last statement executed
   5
}                 # Foo returned 4.
[download]