I don't think it is a problem as long as they are not strung for excessively long amounts of time. After a while I think they may start to loose poundage, but it doesn't happen very quickly. During hunting season I leave mine strung for weeks and have not noticed a difference. I have gotten in the habit on unstringing them though. I think the main problem with limb twist occurs from people leaning them in corners. I would not see hanging to cause a problem as long as the bow is allowed to do its own thing and is not torqued. Personally I lay mine on the floor, or have a hanger that supports the bow on either side of the riser.