Is a lack of understanding of Facebook's privacy settings a viable foundation for a privacy violation charge in the Sumien v. CareFlite case noted below?

Robert Sumien worked as an emergency care technician (EMT) for CareFlite.Jan Roberts, his ambulance partner, commented on the Facebook wall of a third CareFlite employee that she wanted to "slap" a patient that she had recently transported.His comment was brought to the attention of CareFlite's Compliance Officer, also a Facebook "friend" of the third employee, who engaged in an exchange with Roberts.Roberts then posted on her own wall, defending her original comment referencing the need for patient restraints to protect EMT safety.Sumien responded on Robert's wall with the following comment: "Yeah like a boot to the head...Seriously yeah restraints or actual HELP from PD [police department] instead of the norm."Roberts and Sumien were subsequently fired.Sumien sued CareFlite, alleging that the company had invaded his privacy, among other charges.Sumien claimed that he had not been aware that his comments could be seen by others from the company.