Trads can't do 5th floor, wfp's can't do insides.
Put the 2 together and you're set.
To call yourself a window cleaner you MUST be able to trad.
If you can't, what do you say to custies that want a shop front done in a shopping precinct or someone wants their insides done or their mirrors or their sash windows on the 8th floor etc etc.
There are two side to a pane of glass, if you can't trad you are potentially losing out on 50% of the available work.
Anyway, as long as the window is clean, who gives a wotsname how it gets that way.
One mans rubbish is another mans treasure.