Would be illegal in Germany ('Schleichwerbung') and perhaps the EU?

I think it is actually covered in EU AI act article 5 (a):

> [...] an AI system that deploys subliminal techniques beyond a person’s consciousness or purposefully manipulative or deceptive techniques, with the objective, or the effect of materially distorting the behaviour of a person or a group of persons by appreciably impairing their ability to make an informed decision, thereby causing them to take a decision that they would not have otherwise taken [...]

It is very broad but I'm pretty sure it would be used against such marketing strategies.