Virtually all push back clearances in Hong Kong are colour coded, whether at the Cargo bays, or the Pax terminal. The only non colour coded pushes are at the maintenance bays, and there would be less than one aircraft a week pushing there (ie, recently serviced aircraft to depart for a test flight). There is a full description of the various interpretations of push back directions in the HK AIP. Push back can be "RED", "BLUE" or for Cathay and Dragon Air aircraft there are a limited number of "GREEN's". The green's are only used at the Pax terminal. At the pax terminal, a rough guide is that a "RED" bush back will leave you with the PORT (ie red) wingtip against the terminal, however this does not apply at the Cargo apron. The only reason that I can think of for doing the pushes this way is to keep "pilot to ground" (I mean the guy plugged into the nose wheel area) orders fairly simple. Many of the tug crews speak little or no English, so a "Keep it Simple" method was instituted. Well. that's what I believe. When aircraft are being towed around the airport (and now there are many) they are not in direct communication with HK Ground (Tower) Control, unless they need to cross a runway. The towing crews work a discreet frequency (called TMR: Trunk Mobile Radio) and the Ground Controller in the tower issues instructions in English to a tower assistant, who in turn (hopefully) re issues the same instructions to the towing crew in Cantonese. Because of the English to Cantonese issue, delays and stuff ups can happen. The alternative is to kick all of the non-Cantonese speaking Controller's (like me) out of Hong Kong and all instructions to towed aircraft would then be done directly from Ground to the tug crews in Cantonese.