Only twice have I checked in before 5am, for 1 day stays, both on lay over with a 16-18 flight connection wait. Needed rest, shower etc, and did not fancy airport lounge for 14hours

Previous times I had contacted local HI hotel who gave me a "Day rate" for a stay of upto 12 hours.
Each stay was cheaper than a normal night, as they can sell my twice room for that night. Alas both times counted as non qualifying rate/stay.

I wish IC's could offer anytime checkin, 24hour duration , i could have used at least a dozen times last 2-3 years.
I think I read one competitor hotel chain does such a thing, not sure which chain, and whether only allowed for that chains top elites?

Also last June at IC Citystars Egypt I was on 10day 5K/night points break, my flight arrived 3am, I just booked extra night for arrival as only 5K to avoid any checkin issues, else I would have tried asking for very early checkin.
I don't think they help here, as for late checkout for midnight flight I was told, free to 4pm only then $20/hour required. I guess each franchise is different, some helpful, others not.