I was recently asked whether I would recommend a semicolon before “Is that fair?” just as it is before “Is that right?” The answer is that right, true, and correct in any of their various forms are in a category by themselves.
The three — right, true, and correct, — are called “tag clauses.” A tag clause turns a statement into a question. There is no need for a tag clause if a question is asked in the correct English form. If it is “Did you go with him?” there is no need for “Is that correct?”
When someone makes a statement that is really intended as a question, then a tag clause is appropriate.
…You drove over 500 miles that day; is that right?
…She had the second surgery in May; is that correct?
When we turn it around, it is saying
…You arrived at 10:00; is that correct?
…Is it correct that you arrived at 10:00?
…He was not a good manager; is that right?
…Is it right that he was not a good manager?
“Is that fair?” simply does not turn the statement into a question. It does not work to turn it around.
…She was appointed manager of the department. Is that fair?
…Is that fair that she was appointed manager of the department?
In the last sentence, I don’t think the meaning is the same as it is with correct and right. The question now seems to ask “Is it fair?” which puts an entirely different meaning on the sentence.
There are many of these sentences that follow statements:
…Is that what you are saying?
…Is this a fair question?
…Is that it?
…Is that okay?
I would restrict the use of the semicolon to right, true, and correct and their variations as the only three that use a semicolon. The others take a period.
…You came upon the scene about 4:00; is that correct?
…You came upon the scene about 4:00; is that right?
…You came upon the scene about 4:00. Is that what you are saying?
…You cam upon the scene about 4:00. Is that fair?