Yes. You rewrite the "namespace" to "trap" the access to the variables ... example

package mything;

# do not variables (scalars, arrays, and hashes)
    .
    .
    .
my $someVar = 'XYZ';


# define lvalue subs to "trap" access to vars

sub someVar : lvalue {
    print "Ooo! I trapped you!\n";
    return $someVar;
}
    .
    .
    .
1;
[download]

Or something like that. You'll have to work out the details.