The criteria are up to the host, IE: the person doing the work. That's how it's always been. We might be able to infer what's likely but technically we won't know until we have a host, and that person makes their decision. There wouldn't necessarily be two options because whether to distinguish them in the first place is, of course, part of the decision.
If someone feels strongly that it should be one way (or that it should not be another), well, all the more reason to volunteer.
If someone feels strongly that it should be one way (or that it should not be another), well, all the more reason to volunteer.
