I can remember reading somewhere that, in the mk5, there is a command which tells the fuel system to prime when the drivers door is opened after the doors are unlocked...
I can't say I've ever noticed anything happening on my golf, however I was driving a 2010 seat ibiza yesterday and noticed this happening upon opening of the drivers' door. I know its a different type of fuel system on these engines (standard 1.4) than the Golf's FSI unit, but wondering if this could be contributing towards the cold start problems that myself and some other GTI owners have?