I've not had to canvass, I bought work to start with ,then built round up through recommendations.
I have had plenty of newbies canvass my work and i dont have problem with that, what pees me off is when they say they will do it cheaper , so as others have said its all fair game just go in with the price you think is right, its not a good idea to fall out with all the other window cleaners in the area just as you are starting out, you never know when you might need a favour.