I only see 1 possible downside from making it a walk over:
your fans might be in lesser mood to show up in your next game then when you just lost your game without walk-over.
So I'd also try to field 3 guys and make it a 'normal' game
Overall bot teams (especially the ones reaching the finals) aren't that bad. I've known teams who did want to win and fielded 5 players and still lost to the bots because they underestimated them... But okay...
Apart from that I don't think there is any censequences.
But let me add one last thing: what will happen if for instance you trow the second game, and then by sheer bad luck the 3 best players get injured during the tie breaker in the first quarter?
Would it still be a sure win? since, even odd and rare, it CAN happen.

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