Creatures with trample do they deal trample damage every time it blocks
Nope. Think if it like you have your own plane lets call it Narnia and I (your opponent) have mine call it Pen Island.
When I attack you and you have say {Archweaver} and block my 2/2 vanilla it's on Narnia a completely separate plane than my Pen Island. Thus no trample goes through. So trample only works when attacking :P