Possibly, 2 PIN tries that are rejected can cause trouble. But then, my PIN I knew were correct PIN numbers. Or its that some places unofficially do not like to accept the QCC, and can/may make it hard for the transaction to go through.
Its just lucky that I had a QCC SG sitting at home, and was able to phone up the ""Mastercard Service Centre"" and listen to the UK electronic voice ask me for my 16 digit card number, lah lah, and you have to listen till you get to the PIN stage, for the card to be actually activated.
DO not hang up till you hear your PIN read back to you, even if you know the PIN stays the same from before.
Been using the VGW for over a year now, and no problem with it.