Trying shortcuts that may lead to Hell
A growing number of websites are now asking visitors and users not just to approve cookies but also marketing and other solicitations...
Well...
Cookies are pieces of code that are "placed' either on the web browser or (if persistent Cookies) on the "machine", that allow a Server to gather information on both the equipment/ Software and the actions of a given anonymous visitor or a registered user.
If an anonymous visitor, the "problem" is that whatever those Cookies will gather may end up identifying such visitor in a first stage and end up profiling the identified natural person at a later stage... hence, the need (under the e-Privacy Directive) to allow those anonymous visitors as well as identified users to de-activate non-vital Cookies if they do so wish.
Note: non-vital cookies being those that do not produce an impact on the delivery of the service is turned off.
So, it is a preemptive action that prevents potentially starting processing Personal Data and (above all) Profiling natural persons without them being aware of the Processing Activities over their Personal Data and without any Lawful Basis to do so.
Now, Marketing consists either of advertising on the website, meaning messages that are displayed to visitors while they navigate the website and that is within the "Legitimate Interest" (not GDPR) of the owner of the website... or, reaching out to an identified natural person and conveying a Marketing message (e.g. by email; phone; other...).
Having an unidentified visitor unsubscribing to Marketing on the website means the organization is waving out its Legitimate Interest... not against any law, but also not "advisable" since it can do it in a legal manner and not doing it minimizes its P&L potential ratio (revenue due to potential conventions).
Doing direct marketing means the Data Subject has been identified, so it makes no sense to allow someone whom the organization should bot have identified in the first place, to opt-out from an unlawful activity being performed by that organization... just do not identify that natural person to begin with.
That may end up serving as an admission of guilt...
Now, we still do not know what the e-Privacy Regulation will be (since it still is a Directive), therefore as we stand, this is a short cut to trouble ...