My car's got a better (heated) system on the windsceen washers for goodness sake! And I'd take it back if it leaked in the car wash.
A commercial high pressure washer in very close proximity can be very abrasive and can easily damage more fragile bits of the airplane. I've seen wooden houses with major external wall damage due to improperly done washes.
An even higher pressure version called the waterjet is used to cut through metal.