No one can stop me and my peers from sending meaningless garbage data to each other.
So, if it simply looks encrypted, but acctually contains randomized meaningless shit, how can anyone prevent me from bahaving in this manner, and claim that I've done harm?
I've paid for the service, and I can spam it with trash as I see fit.
This is unfortunately not true in many places. In the UK you can be thrown in prison for failing to decrypt any data in your possession. This means someone can encrypt garbage on a USB drive and slip it in your pocket and make you rot in prison for years.
In the US, you will be held in contempt for failing to decrypt data when ordered if they can show that you "probably" have access to it and it's relevant to the charges against you. This also means prison for many years for failure to decrypt, even if you can't.
I don't know what the accepted jurisprudence is on this, but there are interpretations of the 5th amendment saying that the protection only extends to the authorities being unable to legally compel you to reveal that you can decrypt the data (and, by extension, that you have some level of knowledge of or responsibility for it). That is, if they can somehow prove that the data is yours, a court can order you to decrypt it.
So, if it simply looks encrypted, but acctually contains randomized meaningless shit, how can anyone prevent me from bahaving in this manner, and claim that I've done harm?
I've paid for the service, and I can spam it with trash as I see fit.