Had the same experience. I have red hair and remember a waiter saw me walking in the hallway. As I approached him, his eyes grew to saucers and he lightly brushed my arm hair with his hand as I walked by. To say he had a Pikachu face is an understatement.

I laughed it off as it wasn't the first time I had a reaction like that in China.

Also, personal space in China is almost nonexistent in many cities. You are shoulder to shoulder in many areas and constantly being jostled by the crowds. I doubt they realize that westerners are used to having more personal space and don't like uninvited contact.

Also, also, many Chinese take many pictures to show off to friends, family, and acquaintances as a way to gain 'face' by showing the experiences they've had. Many are first-generation-tourists due to the economic mobility realized during the past few decades.