Ok, I concede that my comment about playing a legit copy before release online is clearly wrong 
However, the other points I was trying to make still stand. MS used to ban consoles, not gamertags. This was when it was easy to detect copied games and hacked firmware. It's now extremly difficult to detect the pirates if they are using stealthed rips of retail discs. They now appear to dish out gamertag bans on the following criteria:
- Playing games weeks before release.
- Playing review copies.
My point was that if the bannings were simply due to playing the game early (which is what the ban notice states btw) then it wouldn't be wise to play even a legitimate copy online prior to release. It appears that the leaked game was a review copy, so yeah, it'll probably be fine to play a legit game online.

However, the other points I was trying to make still stand. MS used to ban consoles, not gamertags. This was when it was easy to detect copied games and hacked firmware. It's now extremly difficult to detect the pirates if they are using stealthed rips of retail discs. They now appear to dish out gamertag bans on the following criteria:
- Playing games weeks before release.
- Playing review copies.
My point was that if the bannings were simply due to playing the game early (which is what the ban notice states btw) then it wouldn't be wise to play even a legitimate copy online prior to release. It appears that the leaked game was a review copy, so yeah, it'll probably be fine to play a legit game online.