"Sand Collapse Kills 9-Year-Old at Oregon Beach" by Alex Norton

      A young girl and her siblings were digging a hole at a beach in Oregon when the sand collapsed on the girl and she was stuck for about 5 minutes. Police and Fire Fighters pulled her out and she was unconscious and not breathing. After being rushed to the hospital, she was declared dead. The Mayo report then stressed the dangers of dry sand burial. Currently, no national standards exist to restrict the depths of holes, though local jurisdictions often set their own rules. For example, in Virginia Beach, Virginia, the USLA's home base, beach visitors aren't supposed to dig holes deeper than knee-level, even for small children. Articles over the past decade, including the Mayo report, have called for public health and safety officials to be more aware of sand dangers.

http://www.cnn.com/2014/08/31/us/oregon-beach-collapse/index.html?hpt=us_c2

The fact that I have never heard of an incident of this sort before, goes to show the importance of making this risk known. Even though dry sand burial is not a common issue, it is an issue nonetheless, and the people need to be warned. Restrictions must be made.