I wonder if this will wind up coming down to a jurisdiction issue, or an inappropriate use of force issue.

Jurisdiction is a tricky matter. In law enforcement, four types of jurisdictional areas exist; exclusive, concurrent, partial, and proprietary. Tribal officers have exclusive jurisduction on their lands and their property. In general, law enforcement officers are given authority to act, in other words, what you can and can't do, through a variety of laws, acts of congress, state laws, legislature, etc. otherwise known as enabling legislation. Boundaries of authority such as reservation boundaries, county/state/national lines, park borders, etc are clearly defined in the these laws, rules, and regulations.

When law enforcement officers act outside of their jurisdiction, in most cases, they are treated as "highly armed private citizens" liable under tort law, and for criminal and civil offenses. As has been said a number of times, unless these tribal members were granted law enforcement authority through the appropriate body (in this case I would think the state) they were acting outside of their jurisdiction. The exception to this is when a commissioned officer takes action to protect a person or property from acts of violence under the Good Samaritan Act. I doubt that by any stretch of the imagination anyone would try to make a GSA case out of this issue.

Putting ethics issues aside, the facts of the "case" would seem to say that the hunters had a permit to take an animal, which they did, in legal fashion, on lands that they were granted permission to hunt.

If the tribal officers were outside of the area that they had been granted law enforcement authority, and their acts were not made to protect and individual or themselves from harm, but rather to prevent/penalize the hunters for suspected wildlife/hunting violations, it would seem as though they in for a bit of [censored]-storm. Add the fact that they drew weapons, illegally detained people for what might be considered an "unreasonable" amount of time, things could get ugly.

I suppose it will all depend on what the judge has to say though. Judges and magistrates hold a magic wand that is not always impartial and consistent.