Auctioning Properties: When a player lands on an unowned property and chooses not to buy it, the property must be auctioned off to the highest bidder. This rule speeds up the game and ensures that all properties are eventually purchased.
According to Twitter user Ruben, when a person lands on a property, utility or train station and decide not to buy it, it actually goes up for auction. He wrote: "When someone lands on a property in #Monopoly & they don't buy it, IT GOES TO AUCTION for any player to buy. IT.
