OK. I understand. Joint infringement is a bad thing. I should try describing the method from a single actor point of view. By the way, which actor is the best?
If I were to mix the operator actions, and the device actions e.g. I dial a phone number, and the phone is creating a voice over IP channel = dialing a phone number, and creating a voIP channel. Would a person say he didn't infringe because he didn't create the voIP channel, but just dialed, and the device manufacturer would say that his device does not infringe because it doesn't dial the numbers, but just interpret dial actions of a user?!
In this context, I would think that the human operator is the best actor ... because it is possible to prosecute a human, whereas how would a device be prosecuted? With that in mind, the manufacturer is also a good actor, although defining a method claim with the manufacturer as an actor may be impossible, because usually the manufacturer doesn't participate in actions of the device.
This is even a bigger problem than I thought - my favorite actor, the human being can't create a voIP channel, so maybe it is not possible to define the method from the human operator perspective. Even if it was possible, is prosecuting end users feasible? With the phone as the actor, I can define 'interpreting a dialed number' and have it defined from the phone's perspective, but then I wouldn't be able to prosecute the manufacturer, or the human operator, would I?