Cambridge Scholars Invent Scheme to Track Stolen Bitcoin

The original article here: https://bitcoinnews.com/cambridge-scholars-invent-scheme-to-track-stolen-bitcoin/

Always interested in a bit of blockchain analysis but not sure what to make of Cambridge scholars who still think First In First Out works with Bitcoin. Or am I misunderstanding the FIFO concept? Far as I recall coin age isn't any longer a priority, and most clients now allow coin control, I freeze and mix utxos all the time. Doesn't everyone?

Or am I having minnow brain?