The locket and tabeez that the grandparents tied around the neck of the young ones weren't, after all plain superstition. They served another purpose : of applying light pressure on the upper chest
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/tabeez-and-acupressure
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/indian-express-new-delhi
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/health