UpdatedSat, May 22, 2021 at 1:12 pm ET Replies(10) Businesses still have a right to keep mask mandates and other restrictions in place — and as of Thursday, Simon malls still planned to require masks. But that changed in an announcement on Simon's website Friday. (Dan Libon/Patch) BRAINTREE, MA — The Simon Property Group, which owns 13 shopping centers in Massachusetts, won't require fully vaccinated customers to wear masks when shopping inside its malls, beginning May 29. Businesses still have a right to keep mask mandates and other restrictions in place — and as of Thursday, Simon malls still planned to require masks. But that changed in an announcement on Simon's website Friday.