often, hotel front desk folk will have me fill out the form they turn in to the coppers at night, same form most places now & the past years, some fill it in as their job discription implies.
There IS a box asking for entry date on the hotel regestration form.
I've found many hotels in touristy places often won't fully fill out the form, some don't even copy passport front page, but by written law, they are suposed to.
In Zhuhai once, the desk guy came to my room a few hours after I checked in to tell me the psb said my visa is Way expired, turned out when he filled in the form, he wrote an ols visa number, `just wrote the first one he opened to. He changed visa numbers on the form & left.
He never wrote entry date on the form.
I had one stamp that was unreadably 3 months last year, I just told them a date by looking at my visa issue date, I entered next day, worked fine, but the stamp was there to not read.
My current visa issued June 2 was very simple to get in HK, next day service.