All of the Shoreline Model Raceways tracks have XLR connectors which eliminate the problem of miss-connected controllers. Some of our tracks have screw post connectors as well.
My HO club has several solutions to the problem of the same people winning all of the races. A most events we have chooser races, that is the people will have to choose between two different classes. Often we the final event of the day will be a consolation race for the drivers that did not win that day. Looking at the results for the last season there was hardly anyone that did not win a race.