I think that the people who don’t want to use your aff links will open a new browser window and type the URL directly. I think the majority of people won’t care/know what the aff link does/means and will click on it regardless.
What I ended up doing on my sites to enhance my tracking of signups was to make each banner/link go to a page called signup-casino1.html. That signup page is simply a new blank page with a refresh redirect to my affiliate link as well as my tracking code. Voila, I can not only track when people click on my banners, but they also don’t see the aff code junk. But the main things I am concerned about are how many people clicked on sign up now, and then I can compare that to clicks on the casino site end. I am not a SEO expert, but I think this also helps since all of your banner links are now internal pages rather than external links.
Keep in mind that those die hards who think using any aff link will give them bad luck/less payouts/whatever, will probably still type the URL in rather than click any banner you have.
CBW