I've never heard of this before. Why would it having solid sides stop the airflow? You're not draping a blanket over it or anything are you? I'm quite baffled to be honest. I had my daughter in a basinette when she was a newborn before I decided to co-sleep and all I ever heard about them was the usual stuff - put her in with her feet at the bottom of the basinette, don't leave toys and pillows etc in it, and check that it's sturdy. I think it'll be fine, I really don't see why not.