Even if the Wang family's own properties are well-managed and the accounts are meticulously done, what about those joint ventures established with their in-law families?
From the Keep Achieving Commercial Firm, Changning United Manufacturers Department, to the Qingluo Development Company, and so on and so forth, the Wang family has no lack of ventures co-founded with their in-law families. Within each venture, many members of the in-law families hold positions, and the Wang family's management over them is clearly not as strict as it is over their own clan members.
Such joint ventures have always been hotspots for tax evasion and underreporting. Just a cursory investigation would surely unearth issues.
When the time comes, one simply has to report it upwards, and the credit would be as good as picked up off the street.