There is a discontinued forum from 2010 regarding avoiding Alamo in Union Square. Two years later we had exactly the same experience - two hour wait caused partially by counter staff who tried to upgrade everyone on everything. When I refused a free upgrade of the car if I paid to upgrade the roadside recovery I was then told there was no car available and I would have to wait until one became available. There are several other car rental offices nearby and not one had a queue. The queue was not because it was a busy time it was specifically because of Alamo - they were the only office with queue ropes on the pavement as they expected queues. DO NOT BOOK A CAR FROM ALAMO IN SAN FRANCISCO.