If you let your kids use those headphones at media centers or music stores, it is the same as sharing a comb with all the people who have used it before. Lice can climb into their hair this way.
Also, here are tons of natural and nontoxic, tried and true tips on lice treatment and prevention. Some of these I have never heard of. Here is the link:
Robin, this is very timely advice. Kids will be starting back to school any day now in many areas. I only wish I'd had this kind of reminder when my kids were young and we were fighting the "lice battle!"