Wow. I don't see how they can do that. Either somebody imagines they have too much power, or it's an empty threat. There is no biblical precedent for that and I would definitely challenge it.
Yes, I have been the subject of a local needs talk more than once. When I was 19, my mother was in the hospital dying. I didn't want her to die alone so I lived in that hospital for a week--eating and sleeping and holding her hand. Some of my friends from the hall would come down so I wasn't alone all the time and we would play cards and visit in moms room. The doctors said it really benefitted her because even tho she was in a coma she could hear us in her room. One day, after only a little sleep for days on end, my brother and friend and I got into an ice fight in the cafeteria. Nobody but us were in there and we threw a little ice and then sobered up and went back to mom's room. Less than a week after Mom had died and we had the funeral there was a local needs about apropriate conduct in the hospital when visiting family. They even mentioned a group of young people having an ice fight and bringing reproach upon Jehovah. Everybody knew it was me and my family. I felt like they had publicly kicked us when we were down. I don't know why I didn't leave that f@#*ing organization then.
The other time, I was 21 and gotten heavily involved with a young brother in the hall. We were both publicly reproved. The week after our announcement they had a local needs that was so strong, everyone to this day assumes we had sex...which we didn't. Though now I wish we had so I wouldn't have wasted the next 20 years in that religion.