Yeah, any time you aren't fielding 5 players, the remaining spots will be filled by Lucky Fans, who will play during the game but not show up on the stat sheet afterwards. The walkover issue is different, though. If you start out with 5 players and 3 foul out, you'll get the lucky fans. If you start out with 1 player, you'll get a walkover, where you automatically lose 25-0 and lose out on a lot of training. Your team will still play the game with your 1 player and 4 lucky fans, but the game won't count, and it'll show up later as a 25-0 loss.