I always thought these things were dangerous:

We’ve recently learned that the Consumer Product Safety Commission (“CPSC”) has announced a voluntary recall on Tots in Mind Playard and Crib Tents. The item is a dome-shaped, white-colored mesh tent designed to fit over playards and cribs manufactured by Tots in Mind, Inc.

Models included in the recall:
Portable Playard Tent
Original Cozy Crib Tent
Cozy Crib Tent II
Crib Tent for Convertible Cribs

No model names or numbers are located on the tents, however they can be identified by the pictures in the links above.

CPSC is warning parents and caregivers who own these products that infants and toddlers are at risk of serious injury or death due to strangulation and entrapment hazards presented by these products. The crib tents and play yard tents can present an entrapment and strangulation hazard to infants and toddlers if the dome portion inverts inside the crib or play yard, or if the product becomes partially detached from the crib or play yard. CPSC is aware of 27 tent failures including one fatality and one serious head injury that occurred between January 1997 and April 2012 from crib tents and play yard tent made by Tots in Mind, Inc. Tots in Mind recalled these cribs in July 2010 and offered a repair kit that is no longer available. The company is no longer in business. CPSC staff urges parents and caregivers to stop using the crib tents and play yard tents immediately. Do not attempt to repair these products.

The announcement from the CPSC can be found at: http://www.cpsc.gov/cpscpub/prerel/prhtml12/12179.html?tab=recalls