No ill will meant, grumpy.
I've seen it posted on the boards too, but I've been in the park pretty much every other day and according to the PS system, there are seating times all the way up to about 15-20 minutes till park close at most of the MK table svcs.
I think that people are either mixing up availability with operating hours (the latest ps that was available when I tried to book was 4:30, therefore the restaurant closes at 4:30) or people are trying to walk-up after the last walk-up seatings are over and going to the same conclusion.
October is a fun month for PS at MK, as S,W,F are NSSHP days, when the park closes at 6pm and only LTT is open for the event (those days, the last seatings are at 5:45 indeed.)
Also, Nights of Joy and nights with 6 pm closes (which happened in Sept) will cause that type of schedule.
I have seen the Plaza close that early on a couple of nights, which was more an exception than a rule.
I would like to change my original response from "That's not accurate at all" to "That's not entirely accurate."
Again, not trying to single you out, as I've seen other people post this and then gone to work to find that it was not true (even though it might have been true the night before due to a special event or early close).