So lets get this straight. The guy is invited to the stadium , looks up the location, travels there & it is only when he is actually there that it suddenly occurs to him that he was there 12 months previously. Hmmm - maybe spent too much time on the drugs , dude!
I don't have a hard time believing this. If you attend multiple concerts a year, maybe a friend drives, you party...easy to lose track of what concert/party was where