How it usually works, when the bank update my own savings-account passbooks, they show entries for interest-earned and tax-deducted, on the trivial sums involved. I've never bothered to get a TIN, or file a self-assessment return, to reclaim the tax ... life's too short already.
As you say, I don't yet see that principle being extended to automatically deduct 15% from all remittances received by individual expat tax-residents, in the current proposals ... but who knows what the future holds, with a mildly-socialist impoverished-government anxious to fund its promised-agenda ?
Confuscious might have said, if contributing to this thread, "May you live in interesting, but less-taxing, times !"
ps Apologies Mike, I was typing as you posted, you're correct IMO