They also tend to make them stand at the beginning of their lane when they don’t have customers. Apparently a light signaling that they are available just isn’t enough.
Edit: My bad. I’ve never seen this at Aldi or Lidl. Just other US chains like Food Lion.
Hereabouts*, the lanes each have a sign with their number. Glows red = closed, glows green = open. Super convenient, and I’ve seen it across multiple store chains, so it’s not like it’s only one store doing it.
*Southern Germany, observed across different cities, though I can’t vouch that it is universal