It's a proven fact that many customers will not click on an affiliate URL at your site.
Maybe they resent seeing commission paid to an affiliate, maybe they feel less security when buying from an affiliate.
So, suppose they see a link looking like this in the browser status bar
where '123' is your affiliate code.
They may decide to bypass the affiliate code and just type in the home page URL
And that means you lose out on the commission.
< a href="http://......"
return true;" >
(remove the spaces after the first tag "<" and before the last tag ">")
Then 'ABC' will show in the browser status bar instead of the URL.