Where I live, the main supermarket chain's "senior hour" is between 6-7 am. It also includes anyone with certain health conditions regardless of age -- people with COPD for example -- who are particularly at risk. However, from what I've heard it's not strictly enforced. No one asks for a photo ID or a note from the doctor to prove a shopper is a senior or at risk. There is also a limit as to how many people can be in the store at one time; so regardless of age and health, a shopper just can't walk into the store. If the number of shoppers inside is at the limit, people have to wait in line till people exit; then more shoppers can be admitted into the store.
Ordinarily, when I shop, I know what I want and most of the time I only buy what's on the list. I don't dawdle -- in and out as fast as possible. However, most people take their time, chat with people they know and so forth. I can see grocery shopping which used to take me no more than ten or 15 minutes, now taking hours to complete.
I'm sort of torn on the limits thing.
Not that there are limits, but that they are sometimes too low.
For instance, one gallon of distilled water won't keep my household in coffee, so I have to go to multiple stores to get enough water, or I have to bring a bunch of grandkids along and hand each of them a couple of bucks to go through the line with a gallon separate from me. Otherwise, I'd be making two store trips a day instead of one every two or three days.
In terms of people exposure hours, though, that means instead of one person exposed one time to get, say, five or six gallons of water, now six people/exposure events are mandated for the same outcome. To me, that increases the odds of an infection.