A shop owner displaying their goods for sale is generally making an invitation to treat (Pharmaceutical Society of Great Britain v Boots Cash Chemists (Southern) Ltd [1953] 1 QB 401). They are not obliged to sell the goods to anyone who is willing to pay for them, even if additional signage such as "special offer" accompanies the display of the goods. (But see bait and switch.) This distinction was legally relevant in Fisher v Bell [1961] 1 QB 394, where it was held that displaying a flick knife for sale in a shop did not contravene legislation which prohibited offering for sale such a weapon. The distinction also means that if a shop mistakenly displays an item for sale at a very low price it is not obliged to sell it for that amount.[2]