It seems there has been some form of separation at all venues, the exception being MSG where U2.com members were going to get scanned first, but it didn't work out that way. There was very heavy rain for the first two nights at MSG too, so that may have been a contributing factor.
I'm in Detroit, hoping to get out to the GA line at by noon. Unfortunately my wife may not be able to join me until later (have to wait for the babysitter)...will she be able to join me in line? Just plotting out my days strategy!
Generally fans do not like people saving a spot for someone...if possible, you may want to consider having someone else with you holding her spot till she can get there.