Since your team booked the arena for your game, your players use that time to train.
Very very misleading. The game actually takes place between the team that shows up and a bunch of lucky fans. Yet also at the same time the game doesn't exist because its a walk over. Its a bizarre case where a thing happens and at the same time it doesn't happen. I don't know if its a quantum physics joke or a 1984 reference.
Yes you get training, and GS minutes which won't be the same as you would have got with your possibly carefully constructed lineup, and possibly your game shape and training could be screwed for the week because someone doesn't show up for a game, but hey, at least there's a chance you can have a player injured so that's a big plus.
I remember when Marin said he was going to do something about the scourge of empty lineups as he worded. I thought finall, an end to walkovers. What a disappointment to then find he meant the blank lineup and a change to the let coach decide option, which was the only working option.
Walkovers shouldn't be allowed. Simply force teams to have a default (you could just use the previous games settings if its too difficult to actually force it) or make them play their worst five players for 48 minutes. Or punish them further by making them draft last, and fine them their TV money for the week.
And yes if that means punish someone for forgetting to set a lineup then yes I don't see that as a problem.