pretty sure they take them at Fred Meyer, and probably every grocery store. I think giving credits for recycling the existing bags, bottle returns style, would be a better solution. That way, people who just stop in to buy something quick (like Xericx or whatever he's calling himself these days said) wouldn't be inconvenienced. I prefer the reusable bags anyway, they're much sturdier and never tear.
why do you need credits. if you want to use the burlap sacks, go ahead and use them if you want...not like you're forced to use the paper or plastic.
because it would give incentive for people to return the plastic bags to be recycled. i don't see how that could really be a bad thing.