A Massachusetts arts venue known as Last Ditch Bar and Arts Venue posted on Instagram late last month that Saturday nights would be mask optional. Critics accused the change of putting immunocompromised guests at risk and of abandoning the space’s earlier focus on masking.

The venue later apologized for the way it described the shift. Its house rules now require a KN-95 or stronger mask at all times. Guests who refuse may leave or, if staff decide it is warranted, enter an accountability process.