I had one crazy 4:30am check-in at Hyatt Regency in Sonoma.
Another one was less crazy 6:00am check-in at Grand Manchester in SD

As for the priority check-in benefit definition, can someone point me to it in T&C? I just remembered something that happened to me late last year. When I drove down and arrived early in the morning well ahead of 3pm check-in time, I needed sleep so badly that I almost begged for them to open any room until my confirmed suite is ready. Probably around 8am and hotel wasn't close to full. The guy at front desk told me he could give me a room but I would lose out the confirmed (TSU-upgraded, not paid) suite if I took it. At that time, I was worn out and almost 100% sure that is BS so I took the key without arguing. Later that day, I had no problem explaining the situation and retrieving the suite that I booked.

In my mind, I thought (and was 100% confident that) Globalist was entitled to a regular room upon early check-in if their room, suite or not, is not prepared. Skimming through T&C, I realize that was completely baseless! lol. Also, I do not even see any specific explanation of early check-in.

(f) Priority Room Availability is probably the cause of confusion in my mind but it does not even sound like your check-in time is relevant.

Granted, I did not read the whole T&C thoroughly, but I could not find any mentioning of early check-in let alone priority early check-in.