Hi all. I will be buying this product and understand that if you have a divan bed the straps on the crib go under and around the mattress in order to secure it.I have seen a review which says the straps are even long enough to go around a king mattress.Has anyone actually strapped this around a double mattress?I checked the product out in person but stupidly didn't take measurements and I'm worried the straps are not long enough.Thanks!