One thing to consider is, will Mozilla (or your spam protector) automatically add recipients of your outgoing mail to the whitelist?
If this is not the case, prepare for a lot of unanswered questions. I will not authenticate myself if you sent me a question and my answer bounces, and it's a matter of courtesy to add people to your whitelist that you send a question to - so this must be automated.
Other than that, I think you are fine as long as you explain (and your child accepts/understands) why you are monitoring your childs email ...
perl -MHTTP::Daemon -MHTTP::Response -MLWP::Simple -e ' ; # The
$d = new HTTP::Daemon and fork and getprint $d->url and exit;#spider
($c = $d->accept())->get_request(); $c->send_response( new #in the
HTTP::Response(200,$_,$_,qq(Just another Perl hacker\n))); ' # web