Wallets are most logical places to put Hong Kong identity cards.On my way to the customs, I was waiting behind a 40-50 year-old man, who suddenly bent down, took off his shoe and picked his Hong Kong ID card right underneath it.
It was nothing particular, until I realized I got to put my own ID card in same machine in order to pass through the customs.
Arggh... Sick!
Now, I understand why I was told not to put any article in my mouth when small.
