If you can give me one example I may agree with you.
JUST ONE? --- How about this. I am an Artist, I paint and make scuptures. I have a local storefront where I sell my wares. A local patron comes into my stores and wishes to buy my Art for $15,000 in cash. I am engaged in a business, but it is local only. I have no catalog, no advertisment, and no website furthering or advertising my Art outside my local community.
Being forced to report this transaction, other than legally reporting the income, is a violation of the 4th Amendment. Your thoughts?