The problem with that is that the following script compiles without complaints (even when strict is available) and prints "5". 
sub BEGIN {
  { eval 'use strict' }
}
$not_declared = 5;
print $not_declared, "\n";

[download]
"use strict" is always local for the surrounding block, so you cannot put it into eval or BEGIN.

In reply to Re^2: Making strict optional by betterworld
in thread Making strict optional by dsheroh

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