Most of the schools want OPT student to provide employment(volunteer/paid) details to them within 90 days of start date. To my knowlegde, that information is just for the school and will not release to third party necessarily. It depends on school if they would contact your employer to verify your employment detials.This information will make school that u r maintaining your status. DHS/INS has already given employment time for one year and will ask information only on extension period. Please see response from others too....peace.....