When They Cry - Character Question

[rubyeye]

This show grabbed me from the get-go, but something has been annoying me:

Why does Shion/Mion Sonozaki carry a gun in a shoulder holster ... more importantly, why doesn't anybody seem to care?!

Does it have something to do with her family being Yakuza or am I missing something?

[Nork22]

Think of the gun as 'protection'. I have to read the TIPS again but that's what I can remember about it.

[Fencedude]

This show grabbed me from the get-go, but something has been annoying me:

Why does Shion/Mion Sonozaki carry a gun in a shoulder holster ... more importantly, why doesn't anybody seem to care?!

Does it have something to do with her family being Yakuza or am I missing something?

Its an Airsoft. Its never directly referenced in the anime, and I don't think it comes up in the anime TIPS (though it does in the game ones, I believe). Its just something she does.