The rules of tipping, according to Emily Post’s great-great granddaughter

“Nightcap’s” Jon Sarlin asks CNN’s Peter Valdes-Dapena if used cars will keep getting cheaper and if more EV price cuts are coming. Plus, Lizzie Post, the great-great granddaughter of etiquette icon Emily Post, shares when to tip and when to skip. To get the day’s business headlines sent directly to your inbox, sign up for the Nightcap newsletter. https://cnn.it/3Ilqyqa

00:00 - Welcome to "Nightcap"
00:14 - Used car bubble bursts
04:11 - Tipping point for the tipping debate