"We will not ban any paying customers unless we're absolutely sure they've kept cheating for multiple months in a row. If they tone it down to less blatant levels, we have no choice but to let them continue, instead of banning them for the offences we can prove. Please do not publicly complain about it, or do our work for us, or accuse anyone of cheating, or we'll feel even less sure about our decision and take an extra year to deliberate, just in case."
More seriously though, if you find indicators for cheating in demos, someone points them out publicly, and suddenly they disappear, you shouldn't spend months second-guessing yourself and searching for different indicators. Bring the banhammer down. This isn't life or death, and 99% of the time it's not a coincidence.
An AC team is also supposed to be better at spotting cheaters than the average player. If you've reached the point where random players are correctly pointing out evidence of cheating, you're not banning the cheaters quickly enough. And honestly, the alternatives, (forum) banning people for exposing cheaters or just nicely asking people to wait a few more months (or years) aren't going to get you anywhere good.
If you really need X demos until you're sure, make demos mandatory for everyone, for all matches, all the time. No need to publicly host them, only the AC team needs download access, and no need to keep them for longer than a season or two, so storage requirements won't keep rising. Please don't tell me a paid league can't afford that. That way the AC team can look at a dozen demos whenever they want and don't need to wait a year for a handful to trickle in via the "random" demo requests. Yes, this'll get a lot of people banned temporarily for failing to upload demos, until everyone gets their shit together, but if it also gets cheaters banned, then people will deal with it.
exaQ: Does RGL AC “clear” suspected players of cheating?
A: The RGL AC team does not clear players who have been reported or are being suspected of cheating. Players that have gotten cleared historically have had less oversight from the league and players at large, allowing them cheating, alt, account share under the guise of being cleared. Verdicts on suspected players will only be made once there is a majority opinion with a high level of confidence from the AC team to move forward with a cheating ban. This means that cases for suspected players will always be ongoing until the RGL AC team has a beyond reasonable doubt about moving forward with a ban.
If they have to continuously monitor everyone who has ever been reported forever until a majority of the AC team is absolutely sure they're cheating, then it's no wonder they're not getting anything done.
Without banning everyone or expanding the AC team to keep pace, the workload will increase until the AC team can't function anymore and either ends up informally closing cases anyway, by simply not working on them anymore, or putting an equally tiny amount of time into every case so that it becomes pointless.