I think if you exit the game - in whatever way - to avoid a perfectly valid in-game situation you simply don't like, then it's a bit cheesy.
It's like you fly a totally poverty-spec ship build which you bought when you couldn't really afford it (guilty lol) then hit the reset switch any time anyone interdicts you. Or you're well-equipped, but take on a bounty target - or any other valid target - that it turns out you cannot handle, so you hit the reset switch.
I play in Solo or a Private group exclusively, however I've only done what might be considered a Combat Log once. My reason? Well, I experienced a game bug while in a HighRes site bounty-hunting. It was the old getting marked as Wanted after attacking a verified Wanted NPC. My wingmate witnessed it, we'd both scanned the target and had been sat for a couple of minutes chatting, deciding whether to attack this bounty or wait for the feds to attack first. We chose to go for it lol. Of course, despite only hitting said Wanted NPC once - and he remained marked as "Wanted" FYI - and barely even scratching his shields, I instantly become public enemy number one, with ALL the local enforcement ships near me (about seven or so) going red and starting to attack. I remember thinking, "urgh, this bug again, better flee" and proceeded to do so, but, despite near full shields my controls froze, and I could do nothing. As this entire sequence of events was triggered by a bug, I exited the game. I consider this single "combat log" to be fine, as I was not involved in a valid consequence of gameplay at the time.
So, that was a perfectly valid combat log which was required only due to events unfolding caused by a game bug. I'd do it again without hesitation - especially with a 20 million Credit re-buy! What's not valid in my view, and can get quite annoying even though we're not PvP, is when my Wingmate takes on a target that's beyond him, beyond us when I had a lesser ship, starts loosing, then bails (exits game) and the attacker then instantly guns for me. Even if we agree on a target which turns out tougher than expected, it's not acceptable to just log out of the game - especially when your team mates stay committed.
Basically, to me, the only valid time to combat log is during non-valid game events, such as bugs - of which there are still numerous ones of course. I've only ever had two deaths in the game - I play super cautiously - and both were due to suspect events in-game.
I recall the first, these were both in the very early days after release, I'd just destroyed an NPC that had attacked me. He was just a cloud of dust - we didn't have the chunks of wreckage we do now. I flew through where the NPC had been a few seconds after his demise and instantly blew up. The game seemed to think I'd hit something quite solid, but there was quite literally nothing there. I was in a fairly well-equipped Viper MkII at the time IIRC.
The second time I died I thought it was genuine, though annoying, I got stuck in an interdict/escape loop. I'd be interdicted, escape - chaff & boost - get back into super cruise then instantly be pulled out again. I could not win the mini-game, despite getting my bar all the way into the blue (a bug, it turned out) and would then be pulled out of SC again. Each time, I'd take a little damage from the NPC Pirate who demanded nothing and just shot me. In the end I died. I reported this encounter on the forums, and it was then I was informed that this was apparently buggy behaviour and that I should have "just exited the game" then gone back in as a valid work-around for the bug.
So, those are my thoughts on "combat logging" based on my own experiences. There have been lots of other situations where a "combat log" would have saved me profits etc. but I let the valid gameplay situation unfold. Sometime I escaped a situation with a chunk out of my hull and less cargo, others I actually turned the tide and either defeated my attacker, or forced them to flee.
Scoob.