This is a great question and in my opinion the best way is to notify people what they can get if they win the games or even just by playing such as:
-Getting and winning t-credits which they can use to get amazing prices at the price benders auctions
-They can get and win MRP to purchase items at no cost
-not including all the other prizes they can win
There are many benifites to playing these games even for the people that do not belong to SFI
