@Leebo since I dont wanna keep derailing the other thread about this…the other day you asked
To which I replied
The reason I said I couldnt pinpoint it and “maybe” it was so and so reason was because I initially thought the この sounded weird with it and wrote out that as my reply, but then realized I couldnt come up with a reason why that would make any sense so I went with the next thing that came to mind.
Like I said yesterday when we were playing rocket league though, it still didn’t sound right to me, so I went ahead and showed the sentences to my coworker and asked her what she thought of how natural they sounded. Sure enough she said
この車内、なんだか暑いですね : 丁寧だけど言ってもおかしくない
And when I asked if there was a reason she wouldnt say the second one, she said the この. Her reasoning was that it implies youre currently on the train saying it to a friend, which makes using 電車の中 weird. If you used その電車の中 with a past tense adjective to say that the train was hot after the fact, she said that would sound natural, but using この with it when youre actually in the train sounds wrong.
Why the hell that is the way it is, I don’t know, but apparently my intuition isn’t as wrong as I thought. Its obviously a sample size of 1 so no guarantee every japanese person will say the same thing, but at least I’m not alone.