So my friend is here on a Student Visa, and he has a HKID. When the visa comes in your passport, it reads 'valid for one entry', which he did when activating the visa. If he leaves HK is the ID card all he needs to re-enter and this won't invalidate his visa? (We want to take aquick trip to Macau). The reason I ask is that when we were in Japan it was necessary to obtain a re-entry permit if you wanted to leave and return on the same working/student visa (bascially a gaijin tax).
I'm 99.999% sure that you don't need such a thing, but he's not inclined to risk it.
Can someone set my mind at rest?