BMW question ( pwr steering)

[MS Fowler]

A friend of mine has a 1997 5 series BMW ( in addition to his 300TD). He just had some minor work done on the BMW at the dealer and they advised him the car was " unsafe to drive". According to the note on his invoice the power steering hose and pump leaked and destroyed the steering rack. This seems very suspicious to me. Can anyone explain the cause-effect between a leaking hose ( and pump?) to make the rack fail? Seems like a lazy tech just trying to get him to pay for the whole system. It is making some amount of noise, but the dealership's solution seems a bit extravagant. It also seems odd that all three components fail together.