I found this tip in GDPR preparation discussions as an action item we should take to ensure cookie compliance (in addition to setting up a cookie preferences center on our site/Marketo landing pages):
Add a link to your company Privacy Policy page enabling customers to opt out from Marketo tracking. Link should be https://"customer page"?marketo_opt_out=true. When they click, Marketo places a "mkto_opt_out" cookie on the browser and their activity is no longer tracked online.
1) Can this be any page URL - i.e. fourseasons.com/meetings_and_events/?marketo_opt_out=true?
2) Are you also taking this step? Our legal dept. most likely will not want to customize our global Privacy Policy this way for one tool for one department.
This feature can be useful, but it doesn't give the full-spectrum privacy protection that you're promising to end users.
When you add this param to a URL -- and yes, it can be any page -- Munchkin will set a "no-cookie cookie" and not perform any future tracking in that browser. But if you've told the user that by clicking that link, "they won't be tracked," this isn't true, because the moment they click a tracked link on another device, you will be tracking them again.
To cover all these bases it's more important to persist those privacy settings to the lead record and make sure to honor them everywhere (not sending them tracked links, not loading Munchkin once you know who they are). Stopping Munchkin from loading is pretty simple with or without the marketo_opt_out; it's making sure to honor the user preferences everywhere that's complex.
IMO, it's very important to fulfill the commitment that you make when somebody opts out, to the fullest extent technically possible. A false/incomplete opt-out can be more pernicious than not offering the option at all.