The “cover the table” strategy involves making many bets at once, combining both inside bets and outside bets. By making many bets, including some that have a better chance of winning (the outside bets) and some long shots (the inside bets, especially the “straight up” bets on single numbers), you do affect your overall risk. But you can’t overcome the house edge. This way of playing involves betting a lot more at once, which may or may not be something you want to do.