Wrong. Lexical variables declared inside an if BLOCK are not visible outside that block (and its associated else/elsif BLOCK). perlsub:

The "my" operator declares the listed variables to be lexically confined to the enclosing block, conditional ("if/unless/elsif/else"), loop ("for/foreach/while/until/continue"), subroutine, "eval", or "do/require/use"'d file.

As can be seen:

502 $ perl -we'use strict;if(1){my $foo="foo"};print $foo'
Global symbol "$foo" requires explicit package name at -e line 1.
Execution of -e aborted due to compilation errors.
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The scoping rules work as they should, but the memory usage could definitely be more conservative.

edit: beaten