I would say that this is a perfect example of an opportunity to follow Otto's example of putting code in a site-specific Plugin. I created a Gist for the very simple Plugin drop-in code:

<?php
/**
* Stop Skype from hijacking phone numbers
*
* Adds a META tag to the HTML document head, that
* prevents Skype from hijacking/over-writing phone
* numbers displayed in the Theme.
*/
function mysite_skype_meta() {
?>

<?php
}
add_action( 'wp_head', 'mysite_skype_meta' );
?>