Emily says, on Anne's site:
Believe it or not, they are the official mottos. Each state only has one official motto (though occasionally a state will change it).
However, a state can have many slogans; they are typically used for advertising purposes, such as "Vacationland" or "The Sunshine State".
The mottos are often written in Latin on the flag and other official documents, so many people are not familiar with a motto even if they live in the state!
Thanks for visiting Two Eyeballs. Maryland's is definitely the most eyebrow-raising...
She offers shirts and other goodies with the individual states, as well, in her gift shop.