There exists a client that utilizes a wordpress blog, as he pastes within our video embed code it changes &'s into & so for any workaround he needs to re-write & as &

Performs this break code? Would doing something similar to <code></code> in wordpress fix the problem?

Example:

<param name="adServerURL" value="http://plg.website.com/dynamic_preroll_playlist.vast2xml?domain=111aaabbb&amp;pubchannel=KidS&amp;" />

I am not certain of that which you mean, as the text describes altering &lifier into &lifier. Most likely you meant altering the ampersand letter &lifier to &amp;, but here you should utilize the “” button to “escape” it to really make it visible.

It’s a proper change. In HTML, the ampersand includes a special meaning, which is applicable to occurrences in Web addresses, too. Mostly you will get away by using it should you not “escape” it, but getting away may be the right factor to do—failing to do this may sometimes break the code.

Using <code> markup doesn't have effect on this.

Technically yes they're the same factor. Becasue it is wordpress I would suggest while using &#038; as this is the encoded version from the ampersand & or &amp;.

WordPress references:

http://wordpress.org/support/topic/how-to-get-rid-of-amp-and-038

http://wordpress.org/support/topic/unwanted-characters-038