How are you defining "banner blindness"?
The foundation of LLMs is Attention.
"Banner blindness [...] describes people’s tendency to ignore page elements that they perceive (correctly or incorrectly) to be ads." https://www.nngroup.com/articles/banner-blindness-old-and-ne...
So people can focus their attention to parts of content, specifically parts they find irrelevant or adversarial (like ads). LLMs on the other hand pay attention to everything or if they focus on something, it is hard to steer them away from irrelevant or adversarial parts.
Banner blindness is a phenomenon where humans build resistance to previously-effective ad formats, making them much less effective than they previously used to be.
You can find a "hook" to effectively manipulate people with advertising, but that hook gets less and less effective as it is exploited. LLMs don't have this property, except across training generations.