Dictionary.net

• A petition with the signatures in the form of a circle or round ribbon, so as not to show who signed first.

1899 - The american dictionary of the english language.
By Daniel Lyons

• rownd-rob'in, n. a name given to a protest signed by a number of persons in a circular form, so that no one shall be obliged to head the list. [Fr. rond ruban, round ribbon.]

1908 - Chambers's Twentieth Century Dictionary of the English Language
By Thomas Davidson