The problem that U2 is probably facing in terms of tour dates, is due to the NHL labor situation. Most of the arena venues are home to NHL teams, Boston, NY, Philly, NJ, DC, Chicago, Miami, LA etc. and these nights are booked, even though there are no hockey games. Arena owners can release these dates a rolling 45 days in advance, so currently the middle of January. However dates blocked out in March and April, won't be decided until 45 days beforehand, or if the season is postponed. Rumor has it that the NHL will call off the entire season near New Years, so you could see the tour dates finalized then. This is probably the hang up, because the band needs blocks of four or five dates in the cities they normally do multiple nights. Boston, Chicago, LA, New York.