A topic from AEG's L5R CCG Rules forum, copied for Oracle of the Void from a copy of the forum saved in October 2015, so pages it didn't save are missing. Players' names are left out; the rules officials are named. Rulings are as they stood on these dates; later rulings, the rulebooks and the Rules Archive may differ.
A player, 11 August 2009
Game of Sincerity Political Battle: Dishonor your target unbowed Personality: Dishonor a target Personality. His controller loses 2 Honor. Neither Personality contributes Force in this battle's resolution.
Shameful Injury Battle: Even if you control no units at the current battlefield: Negate all current Force bonuses and penalties a target Personality has received from actions. Until the turn ends, negate all new Force bonuses or penalties on him from actions.
If my opponent plays Game of Sincerity on my personality, then I play Shameful Injury on my personality, will I have force at resolution?
Zen Faulkes (rules official), 11 August 2009
If my opponent plays Game of Sincerity on my personality, then I play Shameful Injury on my personality, will I have force at resolution?
No. There is no rule that "contributing no force" is equivalent to "force penalty."