The 1982 Guinness book of records lists myself, John Cresswell, Paul Taplin and Lesley De Wahl as having played the longest game of monopoly. 408 hours in Shanklin Isle of Wight. This record was beaten a few years later by four Americans.
In order for a record to be accepted by Guiness you have to provide them with full details of your attempt, where it will take place etc. You have to play exactly by the rules at the time and have proven witnesses for every hours. You must provide as much supporting evidence as possible such as news clippings etc. If the record cannot be fully ratified then Guinness will not accept it.
Note: When we set our records we played according to the rules at the TIME. I note in fairness that there has been several rule changes which mean a property has to be auctioned if no one buys it when they land on it. I guess that's to ensure a game does not last forever
wrong its more complicated than that. You can choose to not buy it. check the rules...An Auction only happens if someone buys the property, then later decides to mortgage it to raise capital. If they purchase it back before passing go then they can buy it back at the mortgaged rate plus 10%....If they pass go a 2nd time without buying it back the "interest" becomes 20%...After passing go a 3rd time they get one final chance to buy the property back at mortgage rate plus 30% ..If they fail to do so then the property is returned to the bank as "Repossessed" The nominated "Banker" then auctions the property off to the other players.
Me and 3 friends made the Guinness Book of records in 1982 after playing for 408 hours (17 days) Yes ok we had a short break every 4 hours under the marathon rules but we had to provide witnesses for every hour and play by the exact monopoly rules. We also raided a considerable amount of real money for charity. Yes we were young and silly but so what.