As a mental exercise, here is the gamut of negative consequences to spilling the beans to Cai:
-Cai punishment; too many options to easily lay out everything
-Possible loss of White room, gown, and/or pill furnace income/the furnace itself
-Time out?
-If made public, loss of social standing and possible market ban
-Definite loss of social standing among Cai's Council
-Fu Xiang enmity for betraying his trust
-Loss of 200 RSS payment to Fu Xiang, no intel on Yan Renshu
-SuSu likely loses tax exempt status Cai extended as a favor to Ling Qi
I don't see this as an equitable trade for what Cai told us. Let's not forget that we're already in a feud with one sneaky bastard, and that he attempted to poison Zhengui. Now we're supposed to anger a second sneaky bastard, while throwing away our efforts to defend against the first? No way, that is not a tenable situation. We should not be putting our family at risk for the sake of sentimentality towards Cai.
Then there's all the resources we'd be throwing down the drain. If we get put in time out, that's a huge, well, time sink. Fines? Our cultivation and gearing plans rely on our limited resources heavily. Market ban? Well I guess if we get this, we don't need money since it's the only way to spend it on what we need. A friend would not advise that we take these risks; Bai Meizhen would not advise our honesty in this matter. Keep in mind that the affront we would be punished for is stepping on Cai's toes, not truly the harm we caused to others. I don't want any part of a friendship founded on our subordination to their aspirations, at the cost of ourselves and our family.
Ling Qi's actions were dickish, there's no arguing that. What I'm against is revealing it for Cai's sake. Ling Qi has real responsibilities to Zhengui's safety; accepting responsibility for her past actions means swallowing, but not forgetting, her guilt and forging onward, not imperiling him because she is faced with a sympathetic figure.