Skimlinks respects all pre-existing affiliate links on a page, and we do not overwrite any links that already have affiliate tracking. Our script will only re-write unadulterated merchant links without affiliate tags where an affiliate link is available.
We can allow you to blacklist yourself from certain merchant programs. This will remove your account from a particular merchant program. The caveat is that you will not be able to use the merchant program anywhere on your site. If this is something you'd like, please submit a ticket here