Grocery stores change their store music based on age groups and other characteristics that tend to visit at various times. Here’s a mediocre source, I can’t find one anymore that called out stores targeting specific demographics of people based on time of day.

So to me personally, I could infer that if they know old people shop on weekday mornings and young people on weekday nights and weekends, then fiddling around with the price every hour based on perceived ability-to-pay may amount to price-discrimination by age group, gender or ethnicity.