I just tried to enter and after submitting my combo I got the message "You are unsuccessful today, try again tomorrow". I was not given the chance to push the red button.
I contacted Subway regarding my failed attempt to enter yesterday and received this reply in part -
"Apologies for the problems you experienced.
There was a very small window yesterday morning when we actually used up all of our valid iTunes codes for the day very quickly which resulted in the issue that you have raised. This was caused by an unusually high level of entries that morning."
Seems a little hard to believe but if true it means that if the current entry trend continues then most iTunes vouchers will be won in the mornings!
I go to work, so cannot enter until late afternoon/early evening. It seems, unless Subway can change the current system, then I am wasting my time entering the promotion!