If ladder work goes into it then presuming its not high, usaul first floor domestic stuff its still not greatly skillfull, lets talk about big poles or even 30ft and above do you feel comtable giving someone a big pole and letting them lose, I doubt it, because I certainly wouldnt.
You have to be very compitient to operate big poles, fair enough if its your own work your going to be carefull. But someone else wont care, they will whip poles around not looking at the brush, what if they smash a window or trip, what about potentially leaky windows, what about setting up times, what about hoses everywere, all skills. Many many more than using a squeggee and ladder, anyone can clean windows trad and wfp, trad skills dont take long to achive.
You can look at it both ways, and there skillfull in diffrent ways, I admit there is no skill in gettin a pole out splashing a bit of water and done. But its the whole package aswell. Im undecided about this one. I do know and im sure all of you would agree, a standard window infront of some random person with no w/c experience what so ever would clean it better trad than wfp.
ProPole