In the United States, automobile license plates have become a medium for expressing one's personality or beliefs. Some plates already display a state motto or nickname, and others, like Colorado's, are quite decorative. The mostly green Colorado plate has a jagged white field at the top that suggests the Rocky Mountains.

And many states also offer designs that salute special affiliations or causes. War veterans, for instance, can often get plates that reflect their service. Rhode Island has one that shows a bird in a nest; it reads, "Conservation Through Education." One of Maryland's permitted plates shows a barn and reads, "Our Farms/ Our Future." For an extra fee in some states, you can get a license plate that shows your favorite sports team's logo.

And so-called "vanity" plates use letters and numbers to spell out a personal message. One college student, for example, created a plate that read, "NOTDADS," meaning she paid her own money for the car. And so forth.

But states have to be careful that the messages on license plates are not offensive. Virginia, for instance, has an actual "word committee" that inspects each request for a vanity plate. Still, it took Virginia 11 years to send a letter to a resident who had been driving around with a word on his tags that, in Britain, is a derisive term for gay men. Ironically, the plates' owner himself is gay.

Sometimes the applicant wins the fight with authorities and gets to keep a questionable license-plate message. For instance, a court ordered Virginia to allow descendants of soldiers who fought for the southern side in the U.S. Civil War to display the Confederate flag, which is seen by many Americans as a hateful symbol of slavery.

Almost certainly, in states that allow freedom of expression via license plates, statements like "Save the Bay" will pass muster. Anything more clever or subtle is sure to get a good going-over from the word police.