WRITTEN WARNING

At the emigration checkpoint leaving China fo rHK, the officer takes his time with my Passport then looks at me and says tody is 27th! I take a few seconds to remember my main reason for wanting to get to HK for 25th of Jan. My visa for China began 25th December for 30 days so effectively I have been in the country illegally for the last 3 days. I am taken to a waiting area and wonder what is going to happen next. A uniformed officer arrives and tells me I am getting a warning for my overstay as it is my first time for overstaying and I sigh a triplicate form confirming this, the form is in chinese so hopefully that is what I have signed.