Short answers, pulled from the story.
Sir John Swinton was pulled from his horse and beaten by a London crowd who viewed his badge as a symbol of an unpopular regent. He was only saved from serious harm by the intervention of the mayor.
Richard III ordered the production of 13,000 badges in fustian cloth featuring his personal emblem, the white boar, for the investiture of his son as Prince of Wales. This enormous number was intended to create a visual army of supporters.
The Statute of Liveries of 1506 finally forbade the issuing of liveries to those of higher rank unless they were domestic servants or experienced in the law. Despite these laws, enforcement remained inconsistent throughout the following centuries.
Louis XII chose a porcupine with the motto Eminus et cominus, meaning both near and far, to signify his reach. This device was part of a Renaissance transformation where badges became personal devices or impresa.
The House of Hanover came to the throne in 1714 and marked a turning point by ceasing to use personal badges. They replaced them with royal cyphers instead of the traditional heraldic symbols.
Individuals can still be granted a badge alongside their coat of arms, though it requires an additional fee of £1,000 as of January 2010. The revival of heraldic badges in 1906 by the College of Arms under Alfred Scott-Gatty ensured that the tradition continued into the modern era.