Of course, A) the density is going to be worse, particularly for awkwardly shaped objects, and B) that feels extremely unwelcoming.

But at the point that you're locking everything up and making customers show ID to get things, you're still adding friction for the consumers, this mostly reduces friction for the staff in the longer term once it's normalized - by which I mean, lets them fire more staff.

Really, at the point where you're doing this, it'd be much simpler to just have entire locked off sections of the store where you show ID once to get in, rather than individual shelves.

Of course, at that point, you'll see a drop in sales of anything in there, for everyone who didn't bring their phone or setup the app...I just suspect it'll be less than the drop for having individual shelves that require unlocking.

(I also claim that it's a lie that this is purely or even primarily theft deterrence, given the number of times I've seen stores put non-store-brand versions of things behind them and leave the store brand ones out.)

The customer is then required to be accompanied by the staff member to the nearest cashier to immediately pay for the item before continuing shopping.

It's annoying if you don't know exactly what you want to buy, but it works well if you do.

What changed?