Nothing exactly, you can make another account on other instance using the same email. And as it is pseudo-anonymous you can always use a new email and other username and no one will know you are the same person.
Well, there’s also IP address. If you’re savvy you might be able to get around that as well, but it’s deliberately difficult to do sustainably for exactly that reason.
To my knowledge, there is no coordinated sharing of IP addresses between instances. Different instances are run by different people, so it’s very unlikely the IP address will matter.
A new username on a new instance is likely enough that no one will ever know, so long as your posts or comments don’t give you away.
Well, if you’re not a dick you theoretically shouldn’t get banned the first time.
If you are a dick, I imagine you’ll run out of instances pretty quickly, using that strategy. You could keep it up for a while, though. I do worry about the reckoning with spammers that will eventually have to happen on here.
Which website? CSAM is probably the fastest for 99.9% of instances, but Lemmy all federated, and rogue instances can exist outside the commonly federated instances.
Instance dependent
Depends on each instance’s rules, based on what you are referring to.
Account ban? (You not being able to access your account at all) Refer to your instance piefed.social’s rules.
Communty ban? (A community within an instance banning your participation) Refer to said community’s rules.
Can’t interact with an instance? (not being able to interact with all communities using the same instance) Said instance might have defeferated with your instance; contact piefed.social’s admins for clarification. Both parties should be in an agreement for them to federate again.
Cheese pizza is probably one way to get yourself banned (at a minimum)