The sentence is a strong indication that the complimenting person wants to do some small talk.
And is starting with a personal remark commenting on one's appearance.
I am a rather introvert person with some additional slight social anxiety issues.
Wouldn't directly interpret it as "danger", but would definitely get uncomfortable and depending on how good I know the person also anxious.
You know that your timeline is screwed up, when you see this and aren't sure anymore, if it is real or made up.