Way to miss the point...
how are the minimum wage counter staff (who if they are anything like the staff in the UK tend to be those with fewer options - immigrants, young kids with no skills/decent qualifications, the less able) 'narrow minded bleeding heart liberal jerks looking for an excuse to be a victim' ? 
They are stepping in were they do not belong, the complaint department is not at the cashier, however that is where I must go to get directions to the complaint department. if the individual at the counter makes the decision to deal with me and take it personally, that is a choice beyond my control. They are then the victims of their own decision.
For the record, I once walked right pass the front counter and into the managers little cube of an office. Where I demanded my order to be corrected immediately. She basically said "if my staff has made a mistake, I will correct your order, but if you barge into my office again, you will be eating a lot less at the local jail", so I apologized to her, picked off the onions and laid them in the trash can in her office. So I guess women do a much better job at managing a fast food place, because I have not had a confrontation since with a female manager.
