Many secular organizations, such as jails and public hospitals, allow priests and ministers to serve as chaplains. Sometimes the chaplain is also an employee of the secular organization. More likely, a para-church organization or a church employed the priest or minister and sponsors their ministry on the premises of the secular entity. If the minister or priest is accused of misconduct or negligence, the issue of control the priest or minister might be resolved by a determination the minister or priest is supervised by both the secular and religious entity. Or, it might be determined a minister or priest thought to be solely supervised by the religious entity is, while on the grounds of the secular organization, supervised by the secular organization unilaterally.
In Savin v San Francisco, et al, Order Granting in Part and Denying in Part Motion to Dismiss (ND Cal. 2017), the priest was accused of misconduct. The Court held it was a fact question, at that point in the proceedings, whether the priest was supervised by the secular organization, too, or just the Archdiocese that employed the priest.
The issue of control, which I have relabeled “supervisory oversight,” might not be limited to tracing payroll checks. The inquiry might include, for example, access to patient records, access to non-public areas, or whether the priest or minister is part of the services hierarchy and reports to it. Even broad autonomy might have limits that would seem to be a level of supervisory oversight. The identification badge issued to the priest or minister by the secular organization might be “enough” control.
The relationship between the secular entity and the religious entity, and the priest or minister assigned, should be described and defined in writing. This should be considered even if it has never been done before. A Memorandum of Understanding might be sufficient if all sides are disclaiming control but a contract should be considered if promises must be exchanged or if money will be paid.