something like 'Our accountants handle all that stuff and I guess they must have let that house slip through the cracks.'
That opens up the elitist meme bigtime as the average American doesn't have so many houses that their full-time staff of accountants can overlook the taxes on one.
...there really is no good way out of that.
Either portray themselves as negligent or as rich snobs who have so much money they can't be bothered to or are physically incapable of keeping track of their own finances.