Just to vomit out the last of my migraine-inducing ruminations, the list of major issues jumping out at me (and yes, this is me pasting the conclusion of a lengthy back & forth with CGPT):
Lifetime tracking of every disponer
Revenue would need a central register recording every gift/bequest made by every individual, for decades. That’s a huge administrative burden, with compliance heavily reliant on full disclosure.
Information black holes for recipients
A beneficiary would have to know the disponer’s entire lifetime giving history to know if tax applies. If that’s incomplete or wrong, they could end up with an unexpected bill years later.
Rich-network windfalls
Those with multiple wealthy relatives or friends could collect unlimited tax-free inheritances, because each disponer has their own pot. This shifts inequity rather than solving it.
Succession law tangles
Valuation date vs date of inheritance becomes far more contentious when you’re deciding which part of an estate uses up the disponer’s allowance. Add in life interests, reversions, and trusts, and the legal complexity spikes.
Executor conflict
On death, multiple bequests happen at once. Who gets the tax-free portion? Pro-rata split? First-named beneficiary? The scope for arguments and litigation is obvious.
Clawback chaos
If it turns out the disponer’s limit was breached years ago, who pays? The estate? Prior recipients who’ve spent the money? Both? It’s a recipe for disputes and politically toxic recoveries.