I have learned a couple of things using Canada Post.
First, when I bring a package in to be weighed, I make sure they use a printed label. I did have a package returned for insufficient postage after having it weighed and only putting stamps on the envelope.
Second, the key word is 'documents'. I had a PWE with 30 cards in it, clerk pulled out a shipping form. Said I had never filled out a shipping form before. She asks what is in the envelope ... Felt like saying 'None of your GD business." but I refrained. said I was sending some cards ... "Oh, there are documents" she says and immediately puts the shipping form away. Now, I say I am sending documents and generally don't get any grief.
Haven't found any kiosks in my area yet to avoid the hassle.
-- Mike @ VVcards --
Looking to complete OPC and Upper Deck master sets for hockey including Young Guns and update sets.