My 16yo has mood disorder, similar to bipolar, and has had meltdowns in restaurants. My 4yo is a typical preschooler, and has had meltdowns in restaurants. With both of them, the solution has been to take them to the bathroom, sit them down calmly, and explain to them ONCE that the behavior in unacceptable. Then wait for them to calm down themselves. The other patrons can't hear it unless they come in the bathroom, we don't have to abandon our dinner out, it takes the kid away from the potential tatrum audience (a REALLY big deal), and gives us a place to wash off a red and overheated face after.
The 16yo is an incredibly picky eater, so problems similar to the situation with the child in the article have occurred with us. I have left places, but more often I've dealt with the situation in the above manner. It's seemed to work well. I got the idea from a parenting course I took about 13 years ago.
I've also run into people who don't like ANY children in ANY public places. Those are extremely hard to deal with, and I've had my fair share of hard times with them, especially when my child is playing quietly in the library while I'm trying to find the book I want. One *%#*$ woman even called my kid "garbage!" All my 4yo was doing was sitting on the step stool pretending to read a book -- in a whisper! Apparently, the old bat wanted that particular step stool and none other would do.