Baby bumpers?

Like everyone knows, Elle has been pushing her head against the slats of the crib at night. This wakes her up and she cries. We are thinking about getting her a bumper for her crib.

What does everyone think about that? Elle's dad is worried about safety. I have heard bad things about little babies and bumper safety. I have also heard that some babies use the bumpers to pole vault out when they are able to pull themselves up.

Just call me nervous Nelly, but I don't know what to think.