Come on, folks, all the whataboutery regarding Engineering exploits is very counterproductive. We all know what happened and we all have our opinions. But using it to derail the legitimate concerns raised in this thread is petty at best, and at worst will give the impression that you're tacitly condoning the combat logging by using the well-worn armchair lawyer precedent of "two wrongs maketh a right".
The thing is, there is no technical solution to the problem of combat logging that doesn't involve a major rewrite of the code, and an investment in network infrastructure that might well require a monthly subscription to fund it. And while there are some players who would see this as a necessary sacrifice, it's by no means true of all players. So it's effectively off the table.
Which leaves monitoring, analytics and sanctions. Something FD claims to be doing, but which the OP's evidence would seem to suggest isn't happening. I say "seem" because, while I admire the dedication to data gathering, I'm not convinced that five incidents over as many months is a sufficiently high threshold to have hit FD's radar. There have been anecdotal messages on these very forums and on Reddit from people who claim to combat log far more regularly than once a month without any response from FD. Obviously the anonymity afforded by message boards leads to exaggeration and hyperbole so such anecdotes must be treated with caution, and are by their nature not as robust as the experiment described in the OP.
But the raw numbers still seem low to me, and if FD uses that as a get-out I would not be surprised. At some point around the fourth incident I would have upped the ante by taking the alt account to a CG and CLing several times in a single session, to underscore the idea that this is not another random disconnect caused by a flaky connection. But hey, I'm not the one who put the time in here so I'm hardly in a position to criticise. I just won't be shocked if FD responds by saying that one log a month is basically lost in the noise floor.
Either way it's disappointing that the only real solution available to FD is apparently being applied very gently, if at all. It's been said before but I think there's a valid argument for treating all "in danger" disconnects as CL, even if there's a chance it was a flaky connection. If players with genuinely iffy networking want to continue to risk a shadowban that's their choice, otherwise there are two other modes available if the flakiness can't be avoided.
Unfortunately it looks as though FD have gone to the other extreme and may only be tackling the most blatant examples.
[INDENT](Aside: one change I would make to the OP is where it refers to logging out via the 15 second menu timer as a form of Combat Logging. I understand how annoying it must be to Open/PVP players that this "legitimate" exit exists, but if its use is sanctioned by FD then it is not, by definition, Combat Logging of the sort FD are supposedly interested in punishing. It's an issue to be discussed for sure, but conflating the two here does SDC no favours. Personally I would grit my teeth and change that second reference to read Menu Logging. The timer fight is a fight for another day.)[/INDENT]