How do I prevent the constant offer toMention people in your posts with Google+?in Post Editor?
This is a new Blogger / Google+ feature. Like many Google+ features, this one can be refused. Many blog owners, seeing this offer, refuse it - and are never bothered by it, again. Their refusal is retained, by Blogger, in a Blogger cookie.
If you refuse the offer properly, Blogger Post Editor will remember your refusal, and not bother you again - if your browser / computer does not unwisely block cookies and scripts.