Tango, as the OP is talking about UA, you must know that UA has been for decades, the toughest on enforcement of any US airline on agency abuse. Your statement is very false. If what you are saying is that a large agency that practices decipetive or fraudulant practices is forgiven due to volumes, you should ask many agencies that have had their plates pulled. An agency that can deliver volumes to an airline needs that airline more than any airline needs one agency. Look at the airlines that have pulled off of hotwire/priceline (bigger than 99% of agencies.)