The caveat is for those like myself who are contact allergic and sensitive to cross contamination. I also have dermatographic skin and a strong family history of allergies and asthma, but my asthma is thankfully just mild exercised induced. Most of my reactions are a combination of flat rashes, hives, and behavioral. I think precautions should be noted since kids tend to swallow ocean water and the concentration of shellfish in ocean water and shells in the sand is significant.