Members can delete stories from others stream

Hi guys!

I was just playing around in my ES in one of my test profiles "test", and was browsing other profiles. Then I deleted a story that was posted from "millie" to "didee". I thought it would just hide it from me, but then I logged in as millie, and noticed that it was gone now from her stream.

So basically one member can delete stories from another members stream...

Is this a bug, or a setting I have wrong?

Thanks
Katie

P.s I have attached my login details if you need them