What demos do that spectating cannot

A recorded match is the only evidence structure community moderation has ever had. Everything else (reports, accusations, an admin's recollection) is testimony, and testimony does not survive disagreement.

That is the whole argument for demos, and it is a different argument from the one people usually make, which is about highlights.

Spectating is real-time and therefore useless as evidence

Watching somebody live tells you what you thought you saw. It cannot be reviewed, cannot be shown to a second person, and cannot be slowed down.

It also cannot be done retroactively, which is the case that matters. By the time a report arrives the round is over, and the only question that can be answered is whether the accused does it again while an admin happens to be watching, which selects for the least careful cheaters and misses everybody else.

A recording removes all four limitations at once.

What a demo actually contains

Not video. A demo is a log of the game state and the inputs that produced it, replayed by the same engine that produced them.

That is why demos are small enough to keep in volume, and why they can be watched from any angle rather than only from the recorder's camera. It is also why they break: a demo is tied to the engine version that made it, and a game update frequently renders old demos unplayable.

Which means demos are evidence with an expiry date, and the expiry is set by somebody else's release schedule.

The three things they prove that nothing else does

Intent over time. A single suspicious moment is noise. Twenty rounds showing the same behaviour is a pattern, and patterns are only visible in aggregate.

That the admin was right. This is the underrated one. A ban with a demo attached survives the appeal, the argument in Discord and the accusation of favouritism. A ban without one is the admin's word, and on a community server the admin's word is exactly what a determined player will attack.

That the admin was wrong. Equally important and much less popular. A review culture that only confirms bans is not a review culture, and the servers with the best moderation reputations are the ones that overturn their own decisions in public occasionally.

Why most servers do not keep them

Disk, mostly, and the belief that they are only useful for cheating.

The disk argument is weaker than it looks: demos compress well and a retention window of two weeks covers essentially every dispute that will ever be raised. Nobody appeals a ban from four months ago.

The second belief is the more expensive one. Demos resolve griefing disputes, team-killing accusations, and the ordinary who-said-what arguments that consume most of a moderation team's time, which is to say they are most valuable for the mundane cases rather than the dramatic ones, and that pairs directly with what player reporting cannot do on its own.

The policy that makes them work

Three lines, published:

What is recorded. All rounds, or triggered by reports, and for how long they are kept.

Who can watch. Staff only, or anybody who asks. Both are defensible; being unclear is not.

What happens to them. Deleted after the window, including when nobody appealed.

Servers that record without saying so acquire a surveillance problem the first time somebody notices, and the noticing always happens at the worst moment. Stating the policy costs nothing and converts the same recording from something done to players into something done for them — the same distinction that runs through every rule a server writes down.

What this predicts

A server that cannot produce evidence will eventually have a moderation decision it cannot defend, and the resulting argument will cost it more than the recording would have.

That is not a hypothetical about cheating. It is the ordinary week-to-week of running a place where people disagree, and the servers on any long-running listing that still have their original staff are disproportionately the ones that could show their work.

The evidence problem nobody solved

Demos changed what a server could prove about the game. They changed almost nothing about what it could prove regarding everything else, and the gap has widened as the second category grew.

A demo shows what happened in the world. It does not show the conversation in the party voice channel, the message sent privately, the coordination that produced an outcome that looks unremarkable in the recording. On a modern server a majority of serious incidents involve at least one of those, and the best evidence system the medium produced has nothing to say about any of them.

That is not a criticism of demos. It is an observation that servers have excellent evidence for the class of problem that was hardest in 2004 and almost none for the class that is hardest now.

What a server should actually keep

The practical consequence is that a demo is one of three things worth retaining, not the whole answer.

The demo, for anything mechanical: aim, movement, positioning, timing. The chat log, for anything social, which requires keeping more than the window around the incident because the pattern is the evidence. The decision, written at the time, because in six weeks the reason a call was made will be reconstructed rather than remembered, and reconstruction favours whoever is telling the story.

The third is the one nearly every server omits, and it is the cheapest of the three.

Why nobody watches the demos they keep

Servers record far more than they review, which is fine, but it produces a specific failure: the recording is treated as having settled a question that nobody actually opened.

"We have demos" is not the same as having looked at one. A server that records everything and reviews nothing has the same knowledge as a server that records nothing, plus a false confidence that the evidence exists if needed — and it frequently does not, because the retention window silently expired, or the file is corrupt, or the relevant round was never captured.

Checking that a demo from last week actually plays back takes two minutes and almost nobody does it until the evening it matters.