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it's hard to make a general rule in this case
some streamers probably care
some others probably don't
This. That's why it's more of a problem really not on the streaming site but rather on the user themselves, Since let's say the streamers does indeed put the block, that's just on their side, if the user side wants to bypass it they easily can so it needs both parties really to adhere to the rules. Though I'd say rules are dead on the internet since, well, it's the internet. I'd really suggest that they just rather teach it themselves to their kids, better informed than ignorant since ignorance breeds curiosity after all, and would only lead to falling in deeper I say.
Ignorance leads you to false beliefs. You need to be careful following whatever you see on the internet. This example should serve as learning not to just blindly follow what the streamers are telling you, but instead make your own assessment and make sure that you fully understand all those things that you are watching.
Online have a lot to offer, getting curious is not a crime but a responsibility. You need to be held responsible in each action that you'll going to take.
Be informed and allow yourself to understand deeper.