under what conditions can a non-servant/employee agent bind the principal in tort?
I think that the main issue that must be considered is 'contol.' A question that courts seem to ask in this situation where the tortfeasor is not 'clearly an employee/agent is , "whether the principal authorized intended the agent to act on **188 its behalf with respect to the conduct that gave rise to the third party's claim (Vaughn v. First Transit, Inc).”
You said that, "From modern sources I'm getting statements like "A principal is generally not responsible for the physical tors of its nonservant agents."
This is true but the courts have also added to this language the following, But a principal ordinarily is not liable in tort for physical injuries caused by the actions of its agents who are not employees. Jensen v. Medley, 336 Or. 222, 230, 82 P.3d 149 (2003). Rather, a principal is vicariously liable for an act of its nonemployee agent only if the principal “intended” or “authorized the result [ ]or the manner of performance” of that act. Restatement (Second) of Agency at § 250; see also
So it is true that there may not be liability for physical torts BUT you must also look at the degree of control b/c the principal may still be liable. But in the case you described I would argue that there is not enough information to know whether this errand runner was under the control necessary to conclude that the principal is liable.
In Utah the court ruled in a similar case: "The Supreme Court, Henriod, J., held that where employee had been asked by employer's manager to run errand with understanding that employee would be paid mileage for using his own automobile and nothing else, employer was not liable for damage sustained in the collision on principal-agent theory, absent any agreement calling for indemnity or indication that employer was in any way negligent.
Another court described it as follows, "A servant is not one who does only physical acts. Rather, a servant is a particular kind of agent who has a very close economic relation to, and is subject to very close control by, the principal. A servant is one who is an integral part of the business and must submit to the control of his physical conduct and time. Blanchard v. Ogima, 253 La. 34, 215 So.2d 902, 906 (La.1968). See also Whetstone v. Dixon, 616 So.2d at 769. In other words, being an agent does not make you principal liable unless your the type of agent that is similar to a servant/employee.
In describing this distinction, the Washington Court of Appeals stated: “This [a servant] is to be distinguished from a nonservant agent who ‘aids in the business enterprise’ but is not a part of it.... The nonservant agent agrees sometimes to render services and sometimes to achieve results, but he does not surrender control over his physical actions
The answer to your question may simply be that if the principal seems to have enough control over the situation where s/he may change the outcome then maybe liability exist BUT it is also necessary to look at the agreement they have, their past history, whose car was it, etc...General common-law rule is that the right to control the details of a nonservant agent's physical movements is necessary to make the principal liable for the physical torts of the agent.
Either way it is not bone-head simple. Your frustration is correct.
You professor may be trying to simplify it for you guys and say, "hey, if the principal sent this person out to run a task for him/her then there is an agency relationship and there is liability (but really it is not that easy).