I can sympathise. Just 45 minutes ago an 'old girl' said to me, 'Did you clean that window?'
'Yes', I said. 'Why?'
'Oh because I didn't see you do it', she says.
So obviously this old girl must covertly follow me about to ensure I do every window! Bugs me too.
Maybe some people have had bad experiences with 'window cleaners'. I know I recently took a job from a local guy who was seen missing every frosted glass window and when challenged by the householder (who was probably covertly hiding in the shed), he just shrugged his shoulders, took his ladders and walked off.
This guy has a bad reputation though for being a cowboy.
I'm sure 99.9 percent of our customers trust us to do a good job and pay without even checking. They just assume we do a good job and are happy to pay. It's the untrusting .1 percent that wind you up.
And to answer your question, I think there'll always be both the stereotype of your 'jack the lad' window cleaner who does a shoddy job, and the actual window cleaner who does a shoddy job.
No amount of regulation, licencing or training will remove this problem.
So I think it's just something we'll have to put up with; but at least we have the ability to change our own customer's views; simply by doing what we're paid to do; properly.