You need to consider how would such a situation ever arise, that Revenue are looking at returns over decades. There is a time limit, except where fraud or neglect exists. This burden of proving fraud or neglect means that it only happens in investigation cases, where Revenue have strong suspicions of serious wrongdoing by the taxpayer - so small totting errors are not going to be an issue, it'll more likely be the few hundred grand tucked away offshore, or in prize bonds or something that'll cause the problem!!
I've never in reality seen something as horrific as what you suggest happen, and even if a particular Auditor was inclined to be that much of a dog about it, I'd say a District Manager wouldn't want the thing going off to Appeal over something that at the end of the day is trivial...