The Massachusetts Department of Revenue announced specific laws and guidelines for implementing the annual sales tax holiday in Massachusetts on Saturday, August 13 and Sunday, August 14, 2011. Retailers will not collect the 6.25% sales tax on most items. The tax will still be collected for motor vehicles, certain other items, and any single item sold for $2,500 or more.
One of the guidelines says that any sales tax erroneously or improperly collected must be remitted to the Department of Revenue. (This makes sense to me because a retailer should not have an incentive to profit dishonestly, even if unintentionally.)
For the Technical Information Release, TIR 11-7, click here. For all Technical Information Releases that the Massachusetts Department of Revenue has published in since 1974, click here then follow the links on the bottom of that screen.