don't know the answer for sure, but I understand why many fans believe it is
because the home teams know they can sell out United's visit. I suggest you
ask the other clubs that reduce our allocations why they punish United fans
but not those of other clubs who stand in seated areas.
We have defended United fans on a number of occasions when we believe
they have been unfairly targeted. However, if a majority of our away fans are
standing persistently during games (particularly in gangways and exits, which
is a real safety hazard), and the local safety authorities decide to reduce our
allocations as a result, there is little we can do about it.
Bottom line: if the fans stop standing all the time, the allocations won't be cut."