Idaho has an any centerfire rule, its been this way for years. The problem is some people just don't get it, I know of people right in the small town I live in that hunt elk every year with a 223, thats all they have. Now all of us know that a 223 will kill an elk.....we also know it will wound several before one of them drops. Giving some people the benefit of the doubt can be a big mistake, while I'm all for leaving hunters alone to use common sense as they see fit I also know that some people just weren't meant to reproduce!
I don't think that putting a 24-25 caliber 1 1/2" minimum case is going to cause anyone any grief if they are serious about hunting.
Last year in Montana I shot 2 whitetails with my 41 Bisley, on skinning one of them out I found 2 22 rimfire bullets just under the hide. Just my thoughts.

Dick