@Ibri The mining operation went there knowing they themselves would look suspicious and possibly prompt some sort of armed force to show up, because they brought a bunch of friggin' soldiers to the border. The magic stones are literally right on the line on the map separating the territories from the look of things. Normally neither side would've been operating in that area like that because they know it looks bad and the countries are not on good terms with each other.
Mitsuba's arrival was a bit over the top, but she asked to speak with someone and they attacked her instead of seeing what she wanted to talk about first. No one was hurt more than necessary to restrain them and stop their attacks. This is a pretty friggin' peaceful border dispute, all things considered.