[map of visited grocery stores][1]
Legend:
green circle - correct amount charged,
red diamond - overcharged for more than 10 CZK,
pink diamond - overcharged for less than 10 CZK,
gray square - undercharged
Note. The approximate area of the Prague 1 district is shaded gray. A small amount of random noise was added to coordinates of each store in order to prevent its exact identification. When stores are too close to each other, individual markers might not be visible on the map.
[1]: https://osf.io/pgva9/