I suspect that easier retrieval might be a factor. I put USBA targets on a large cereal box stuffed full of walmart bags until it bulges pretty good. Target darts go in two or three inches but pull out super easy. If the center starts to get soft I just pull all the bags out and give them a quick shuffle then stuff them back in. Biggest problem is the darts eating out a hole in the cardboard but this takes much longer than finding another box.Some good ideas here, thanks!
I have a question? What do you get, or are the advantages of shooting at an archery block over say stacked up cardboard?