I've definitely seen it. For example, when I was riding car #3820 on 1/22/20, a set of doors did pop open slightly when the train would roughly brake. I don't see it commonly, but it does happen
6700 seems like an interesting unit. Has cloth seats and also a different number font.
Also the difference in seating between 6690-6728 vs 6729 on (the first pair of seats on the left side of the bus) is cool as well
Have they decided to rope off every car at the ends of the married pairs (since they can shift position anytime) or just the part in the middle based off of the consists' current configuration? If the latter is true, they should leave them in this format to protect the conductors (not shuffling the cars).
Yeah, all of the R62As excluding 1943 and 1949 have cabs on the cars ending in 1, 5, 6 and 10. Guess they're just linking the remaining singles as best as possible now