Why oh why does this not barf

Because you did not use -w.

[localhost:~/Desktop] bbking% perl ./yourprog.pl
[localhost:~/Desktop] bbking% perl -w ./yourprog.pl
Name "main::BAR" used only once: possible typo at ./temp.pl line 5.
Filehandle main::BAR never opened at ./temp.pl line 5.
[localhost:~/Desktop] bbking%
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HTH --

s!!password!;y?sordid?binger?;
y.paw.mrk.;;print chr 0x5b ;;;
print;print chr(0x5b+0x2);;;;;
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