i noticed when i was in vag com a while back, i had a "half rear wiper wash jet" or something along those lines. this option was ticked as default.
the water only jets up about half way up the rear window. the only thing that would come into contact with the rear brake light is probably some light spray.
is this the case on all mk5 golfs or does the washer jet reach the top of the window and consiquently the brake light?