I do believe most hotels will "process" no shows sometime between 2am and 4am each day. Normally, if you check in before that time, you will automatically get credit for that night as you show up as having checked-in and being there for that night. My guess where someone said they checked in after midnight and didn't get credit for that night, they actually checked-in after that day's check-ins/outs were processed. Thus the "system" didn't register them as being there for that 1st night.

So if someone is going to arrive very late (i.e. 7am the next morning) to "increase" your chances of automatically getting night credit, I would try to call the hotel and pre-check in with them earlier that previous day. You could also call the hotel letting them know your estimated arrival time (of 7am the next morning.) They will probably pre-check you in themselves to allow their systems to reserve you a room. If you don't let them know, most likely you will have been marked as a no-show. They will charge you for that night and cancel the rest of your reservation which would make for an awkward check-in that next morning.