I worry about this also. I just bought
http://www.bestbuy.com/site/personal-gps-locator/2750716.p;jsessionid=70C5793A0C8D1B3737C0339CD43477B0.bbolsp-app04-107?id=1219077224583&skuId=2750716&st=pocketfinder&cp=1&lp=1 the only thing I don't like is that it cost 12.95 a month but its worth it.