Tipping
 

question to the hongkong experts: is it common to give a tip in a restaurant? how about in the hotel?

Search function broken? :confused:

thank your for the link.
So tipping is not compulsory in restaurant & taxi.
is HK$ 20 enough for the bellboy?

Tipping is, by definition, not compulsory anywhere ever. If it's compulsory it isn't a tip. For taxis it is positively abnormal. For restaurants you will get a 10% "service charge". You can leave a little more in cash if you are particularly pleased with the service, but it certainly isn't done as a routine thing.
HK$20 is fine for a bellboy unless you have an extraordinary amount of luggage. Even HK$10 is OK for carrying a single bag up to your room (although that might be seen as a bit cheap in, say, the Four Seasons).

Tipping - Official Guidance by HKTB
 

The following is the official guidance on tipping by the Hong Kong Tourism Board:

Q: Will I be expected to pay tips?
A: Most restaurants will levy a 10 per cent service charge but waiters will expect to be given some loose change. Restaurants that don't add a service charge will expect a 10 per cent tip. However, tipping is left to your discretion. Bellboys, porters, restroom attendants and taxi drivers will happily accept loose change.

For further information, please go to www.discoverhongkong.com

At restaurants in HK, the change you get back is seldom with the smallest number of bills/coins.

Say if the change is $51, you will not get a $50 bill and $1 coin. You will probably get 1 $20 bill, 2 $10 coin, 2 $5 coin and 1 $1 coin. They expect you to leave some tips. And not just the $1 coin.

Have anyone seen similar things in other places?

Yeah, like most places in the world.

Also, if you pay by credit card, always give any tip you wish to leave in cash. If not, you're just giving the resturant a little more profit as the staff will never see it!