I just flagged a comment as 'obsolete, chatty' on Music Practise, where I only have under 5k rep, & the comment immediately went... boom, gone.
I've seen it happen on SU & Ask Different too, but most times it just adds a little red flag & the outcome is decided later.
What mechanism makes it just go 'boom' with no review process?
Could it be that I was coincidentally the deciding flag & others had done it before, but the flag isn't shown unless it's your flag?