One thing that I have been paying attention to is the rights to withdraw: Clients and employers seem to be unhappy when that happens, but we know that should be part of the basic rights of the interpreter. We should also have efficient processes to deal with that, so that all the parts involved are not that unhappy.
I think I am sure most of the interpreters would be OK with not getting paid for the jobs where they effectively did not work, so say where they had difficulties, outstanding difficulties, when it came to understanding clients. That is one point because paying for jobs where the interpreter effectively did not work could make employers upset.
A second point is still rights to withdraw for no reason: If we work as contractors, we do have the rights to withdraw for no reason, like we may not be feeling well, we may think there is something that deserves our attention more than that job at that very moment, we may not have the equipment in conditions that are suitable, etc. The reasons shouldn't actually be part of the actions: We are contractors, each assignment is a new contract, and, as such, may be rejected.
A third point is full disclosure of basic details: Some organizations still refuse to give us details of the jobs they are offering to our employer. Because of the nature of our work, and, in special, because we are contractors, the agencies should be legally obliged to disclose at least the names of all parties involved plus topic before we are offered the opportunity of saying yes or no. First of all, one of the clients may be an acquaintance or a relative. We are ethically forbidden from serving those.
I feel as if, different from all other contractors, we don't have the rights to withdraw, like not for real. It may be that the reason is that the employers still pay us if we withdraw. It may be that the reason is another. Yet, if they keep us as contractors, we do have the rights to refuse jobs at any stage of the process. We would gladly accept not getting paid for those, but we still have the rights to withdraw at any time. The cops pass to their fellows when feeling uncomfortable. And they are not contractors!