This is the required replacement code:
Code:
<blockquote class="twitter-tweet"><p> </p> <a href="https://twitter.com/twitterapi/status/$p1"> </a></blockquote>
<script src="//platform.twitter.com/widgets.js" charset="utf-8"></script>
The Javacript looks for the class "twitter-tweet" if it is missing nothing will happen.
No security risk as long as you trust Twitter.