I’ve experienced a few of these over the (many) years I’ve been travelling around.
The most recent one was a southbound Avanti service on a Sunday morning. Booked slow lines & via Northampton from Rugby. It was then a pleasant surprise when shuffled onto the fast lines at Ledburn for a 15’ early arrival at Euston.
The conductor, on arrival at Euston, commented on the early arrival, advised everyone to tell their friends, then followed that with, “I don’t expect they’d believe you anyway’
Good bit of customer service with a bit of fun.