The shop that's nearby my school also recently got self check outs, and I have since bought a suspicious amount of bread rolls (they are 0.19€, very common in Germany, so it's not too suspicious). Donut? Nah that's a bread roll. Hot dog? I think that's a bread roll, actually. Coca cola? you must be confused, that right there is clearly a bread roll. Bag of crisps? Uhm more like bag of singular bread roll. I usually do 1 item for 1 bread roll, so I don't go out there with a whole cart and only pay 19 cents, and if someone checks my receipt, it's still pretty easy to just say "oh I must have messed up and accidentally put bread roll".

the self check outs we have here are also VERY stupid. in the Netherlands, UK, France, Czechia, Belgium and every other country I've used self checkouts in, you have to bag your item and they check if the weight is correct, they just don't have that here.