Before you say anything, I know that it's not the fault of a water fed pole, because the seal is broken and will let moisture in, but it looks from this quote that water might seep in the lower seal, this will happen with traditional window cleaning, but how much more will that happen with a water fed pole? Okay, the window is already bad, but it might get worse with a water fed pole.
Exterior seals not fitting correctly, letting water in:
Again, similar to above, but if some of the water getting in contains washing up liquid or similar, then this will attack and degrade the perimeter seal, usually along the bottom edge. Anything stuck together will come apart quicker if immersed in water, and even quicker if that water contains a solvent or any oil based contaminants.