If the account is private, we cannot be looking through their answer history, only categories. So there should be no "n report limit" by any single reporter... just their trust rating.
If the account is private AND they post anonymously anyway, they should get an automatic "minimum trust" report against their "answer".
We have a lot of Helpline Scammers that are flooding Yahoo Products categories, and insufficient reporters to remove them. The recent changes to reporting, has turned off a lot of people to bothering to report.