Make more money by making sure your links are valid html

[Useless]

Originally Posted by msanchez

Is it possible that some sales would still register with the default code but not as many as would register is using "&" when using a php redirect?

With the php redirect, the web browser doesn't have the opportunity to de-entify the URL. It's like copying and pasting a URL right into the address bar. If you are using that linking method, there's no reason to worry about validation of the php redirect. There's no page to validate.