It is pretty clear that if your staff person was acting as an individual and the organization was not involved, your organization would not be liable for her actions, even if she is prosecuted or held liable for certain damages. 

If she is representing or participating at the direction of the organization, however, it could be a different story.  Traditionally, in peaceful protests, sponsoring organizations have generally not been directly sanctioned.  As long as things are peaceful, no one is hurt, and there is no significant property damage, you probably don’t have much to worry about.

But in recent years, with anger increasing across the country, new legislation is being considered at the state level both to increase penalties on the protesters themselves, and in some cases to impose sanctions on organizations that “conspire” with the protesters to cause damage.  The Washington Post reported in February that “Republican lawmakers in 18 states have introduced or voted on legislation to curb mass protests in what civil liberties experts are calling ‘an attack on protest rights throughout the states’.”  Oklahoma passed a bill (H.B. 1123) in April that imposes penalties on organizations that are 10 times the penalties for individual protesters who damage “critical infrastructure facilities” if the organizations are found to be conspirators in willful trespass or damage to such facilities. 

The statutes may or may not be constitutional, but before you get involved as an organization, you want to be sure you know what the state law is, what is likely to happen at the protest, and what the attitude on enforcement is with the local police, prosecuting attorney, and perhaps the governor.   Protests are important and constitutional.  The Medicaid protests appear to have helped sway public opinion against repeal of the Affordable Care Act.  But as an organization, before you jump into action, you want to know where the lines are and whether you are willing to take the risk of crossing them.