No matter which hotel, make sure the hotel out ur icepack/milk into freezer, not fridge. I had a bad experience that they put it wrongly even i explain very clearly with them.
I have the experience to hand carry 雪奶 through custom in china airport. You can tell the staff that it is breast milk. They will ask you to open the freezer bag for a quick peep. Then they might record your passport number. But no need to pass through x ray machine. Actually this applies to other airport as well.