Common sense doesn't seem all that common. The AAP says this:
http://www.aap.org/advocacy/releases/softbedding.htm
It makes sense to me to follow the recommendations of qualified doctors.
As for a wearable blanket slipping over one's head, try taking a t-shirt off without first removing your arms from the arm holes. Not so easy.
A lot of people have commented that they can't believe they survived, but consider this: There are some people who didn't. There might be more members of this quilt board today if they hadn't suffocated in their cribs or overheated due to unnecessary bedding in their cribs. It sounds dramatic, but it's also true. What parent really wants to take that risk? Remember, it's about keeping a baby safe who can't speak for him or herself; not about making sure he or she has cute stuff in the crib.