I thought that was the case as I had heard a Dragonair guy saying they could take a week off every month by taking 4 days leave and then appending 3 days off (G days) to it.
The CX guys in the conversation all looked at the bottom of their glasses as they had visions of an 8 day pattern followed by 3 days off followed by 4days leave and then a further 8 day pattern..... no wonder you guys are leaving.
Whilst not knocking the ability to append G-days to leave; G days can easily become leave days in the company's eyes.