I own a child care center and I use portable folding cribs for the infants that are part-time (one or two days per week).  While setting the crib up the bottom plate/wooden base for the mattress would scrape the interior of the crib and cause nicks in the finish.  If I was very conscientous I could avoid this most times.  I didn't feel that it was a very sturdy crib so I only allowed infants under 15 pounds to sleep in it and despite my efforts the darn thing broke in half.  I noticed some splitting of the wood above the hinge and when I pulled it out of the closet to really examine it, the rolling wheel came loose and fell out of the joint and the whole thing split in half.  I thank God that no baby was in it when this occurred.  I don't know how this crib passed inspections.  Maybe it's a "once a year at grandma's house" kind of crib and not built to be folded and unfolded twice a week?