Sorry if this is too frivolous. Just tell me nicely if it is. It is very hot, and my mind drifted -- as whose would not? -- to estate taxes.
As many of us know, in the US, any amount may be left to a spouse free of Federal estate tax, but assets of above 11.4 million left to any other person are subject to Federal estate tax.
In the interest of simplicity, ignore State estate taxes, children, and close relatives.
Assume: A (a woman) and B (a man) are a married couple with a hefty, but not ginormous, estate. A dies. B then marries a younger person A'. After some years, B dies and A' marries a younger man B'. And so on. If the ages of A' and B' and A" and B" (and so on) are chosen right, and there is no foul play or even suspected foul play, this could theoretically go on forever. Of course, the sequence would have many A's with younger spouses, but nothing that a visit or two per-older-A to a good cosmetic surgeon could not render almost unnoticeable.
Question: With current technology or technology in the pipeline, would the IRS notice this large estate passing though a long string of deaths free of estate tax, and if it did, would it care?
Disclaimer: The As and the Bs could, of course be a same-sex couple at some or many points, but I'm trying to keep this simple.