Power Steering Fluid problems of the 2008 BMW 535

2008 535i power steering pump at 49,560 miles. I fluid dripping (brownish-reddish) on my garage floor and looked under the car and noticed leak developed under the car engine left side, sipped thru the under carriage cover plate. I contacted BMW dealership, set up appointment for service analysis. I was told by the service rep and his master mechanic that they could not find any visible leakage and could be "just from another vehicle parked on the spot before and just "top off all fluids". I insisted that the drips was on my garage clean floor and un-satisfied with the answer. I told the service rep that I will e-mail him a picture I took of the cars under carriage showing the fluid dripping. After an hour, he called and admitted that the picture help them to "trouble-shoot" and they un-install the under carriage cover plate and found a leak on the power steering pump (part cost $1,250. 00 not including labor, $1,630. 00 total) and need to be replaced. Fortunately it's all covered under warranty. This could have caused total loss of vehicle and cause accident or even lives.