To be honest, everything I know about that is what I have read about the number of cases when platforms or other kind of purveyors of piracy are sentenced to or settle paying tens of thousands, or hundreds of thousands or even millions. Those are real cases where the people involved obviously felt very confident about their legal safety. Surely, most of the situations are not like that and don’t even get to be in the news because of how insignificant the resolutions are.
I'd say not only are most situations not like that, the ones you are referencing are specifically people who were actively sharing content. There are a couple of decades of history on this stuff.
But, is there a way to be sure about what kind of outcome would lemmy.world would get to be completely confident about doing or not doing one thing or another?
Well this is what a lawyer is for. As well as liability insurance (another often misunderstood thing - every group/business/etc is different, but a general liability policy for a million or two USD costs most folks around $1-$2k per year.) But there is quite a bit of established law, yes. If you link directly to materials that would be infringing, but not host, you can be considered as intentionally encouraging direct infringement - note that this is with a direct link only. This goes back about... 20ish years to MGM and Grokster.
Also established - thumbnails are fair use, indexing or linking to a website (but not to content directly) is an intrinsic use/function of websites. If a direct link is made, the site owners need to remove that link when notified either by report or by a claim from the IP holder. There are even safe harbor provisions specifically around sites like Lemmy (and other link aggregators), which a lawyer can provide the guidelines on how to ensure they apply.
Is that just one time? Is that total to get a safe and definitive resolution? Or is that every time the situation arises?
It depends on what we are talking about. Reviewing a specific claim? One time cost. Getting a good general response to any random bunk claim that comes their way? One-time-ish, it doesn't hurt to check in with the lawyer every once in a while to see if anything needs updating. No lawyer I know is going to charge to read their own letter, but they may say "There are some extra references that can be brought in here from recent case law, I'd estimate 30 minutes of work" which would be an extra cost obviously.
What about companies that exist exclusively to massively send takedown requests?
A great reason to have already spoken with a lawyer and have a prepared response. Also a great reason to speak with folks at the EFF should the need ever arise, they like going after copyright trolls.
If the instance openly accepts the legal liability, the number of times that this happens will decrease, increase or stay the same?
Who said there is legal liability being accepted? What liability legally? Specifically.
My position is that the instance admins are not obligated to be a legal shield for the users to have any kind of content that we want on the platform.
No, but this is the part where I think you're missing something really important. The piracy community (communities) aren't the issue to me. Lets recap what happened here.
There was a claim that came in on something - unrelated to these communities. There was, as far as has been posted, absolutely only a request, with no response other than lemmy.world simply agreeing to what was demanded. This has not had any actual legal review, and may have been a completely valid or invalid request.
They then decided to apply this request (valid or not) as a concept to other areas, and simply disabled access. There were supposedly hours of discussion here, and then the change was made, with absolutely zero discussion. There were never any comments expressing concerns to any of the effected communities or the admins of the instances which manage those communities. There was no posting here until hours after it was brought up on another instance. This is also only a few months after they admitted to doing a terrible job of communicating and promising to do better.
There was an unsubstantiated claim from an unknown entity, and their decision on how to apply that (not just to the claim, but to unrelated communities) was done unilaterally and without any legal input.
Forget piracy. There is a trust problem. Why would you feel comfortable providing them with any information of yours if you live in a country where you may be concerned for your safety - not even now, but in a few years - for having the unmitigated gall to admit you are (gay/trans/bisexual/a believer in a socialist meritocracy/atheist/muslim) on a place where there are no legal precautions actually being taken? Where the word of someone sending a letter matters more than what the law might actually say?
My issue with the decision here has almost nothing to do with piracy or those communities. It has to do with trust. And they lost mine.