The past few years I have noticed the increase of the word "banned" when a person gets suspended, especially in the context of American sports. 10 years ago I never heard that someone was banned for 1 game for doing X. Now it is a common headline. When and why were the two words swapped?
Based upon my review of many sources via google, I agree with your assessment that it is a recent phenomenon.
An NGRAM shows ban increasing over the past decades and suspension on the decline over the same period. Granted these are books and not headlines.
I think the popularity of ban vs. suspension in headlines has grown due to the economy of letters. Many of the articles I found said ban in the headline, but suspension in the body. I found a fairly large number, however, that use ban in both places.
That said, phrases like temporary ban, lifelong ban and permanent ban have been used for quite some time. This tells us that the concept of bans being time limited is not a recent phenomenon.
When and why were the two words swapped? I suspect it is a consequence of discipline, and legal ramifications. [Applications to some colleges ask the student whether or not they have ever been suspended. In some places in the United States, a suspension is noted on one's transcript. However, other places do not report suspensions or are expressly forbidden from doing so under state law. Students who breach a suspension (attend the school while suspended) may be arrested for, and charged with trespassing. This could result in an extension of suspension, community service, and sometimes jail time.]
: https://en.wikipedia.org/wiki/Suspension_%28punishment%29#Academia Notably, schools are under political pressure to increase attendance and graduation rates, along with the financial commination of Civil Rights investigations.
David M, it would be informative to meld the "suspension rates" with your graph