Seriously these streamers don't care about their audience.
See YouTubers like RiceGum, JapePual.
And recently I've started watching a streamer from the league community and he's promoting a well known gambling casino to their audience knowing full well the majority of the audience is under 18. But that solves after they put 18+ in the video but does that work for people who wants to break rules whenever they can?
They really don't. Although I'm not following that much those streamers and content creators that focus more on gambling I see them once in a while, people should be careful with their strategy of convincing their audiences. I think there's a psychology impact why these advertisers are also choosing some line of audience like an age bracket that they're targeting through these streamers because they're likely to be the ones that are very much active.
it's hard to make a general rule in this case
some streamers probably care
some others probably don't
copywriters will say that people care only about themselves
we always had psychology impact from marketing in all kinds of ad styles, this is just getting more sophisticated with the use of pixels and advanced tracking systems that can predict what you want or implement desires you didn't have before.
Adblock is a must for surfing web 2.0 nowadays