The biggest issue with self-checkout is that often at least half of them are red/unavailable.
It's not actually a technical malfunction as they are quite robust, it's because management has rules that dictate that only X number of self-checkouts are available depending on how many staff are assigned to monitor them for loss prevention. If they are cheap and only hire one or two people to stand around in the self checkouts, they are going to have a bunch of them off.
