[...]
The abuse happened until late 2018, where everyone was well aware how Merit should be used, how important it was for ranking up.
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Hmm... I stand corrected on the merit cluelessness. I admit that I didn't check the log [I assume the log didn't cover that far back to 2018, just like the archiver by loyce and ninjastic] and thus didn't aware the full depth of the merit distribution. I assumed that both accounts sent a huge amount of merit once, realized or being warned about it [or got educated by himself] and stopped doing it.
If the distribution was spread evenly throughout the year, then yes, I think Haunebu should be, at one point, aware of the implication of his action and continued on doing so before stopped altogether.
I am now torn for the negative, though. I initially inclined to think that even the merit abuse is proven, then the tag should be a neutral one, given the negative dictate,

and on this case, there were no risk [at least according to my opinion, but I am open for discussion] of trading with Haunebu, i.e., he's not scamming anyone. But your reference of what hilariousandco said moved me an inch or two from my stance. I am now not sure what to do.
May I ask your opinion if I counter hilariousandco's opinion for red tag with the one given by theymos, [I stole it from nutildah's on previous page]
- Forgiveness: Often people make fairly small mistakes, but then they seemingly get red-trusted for life. This isn't really fair, and it discourages participation due to paranoia: if you think that you have a 1% chance of running afoul of some unwritten rule and getting red-trusted for life, you might just avoid the marketplace altogether. Red trust should mostly be based on an evaluation of what the person is likely to do in the future moreso than a punishment/mark-of-shame.
if we consider that as it's been five years since both account exchange merits, then it's probably safe to assume that the mistake happened in the past and won't happen in the future. Thus, red tagging them will pose as a mark-of-shame instead of a warning for others.
What's your thought on this?