This matches something the startup I worked at discover when installing power monitoring equipment in restaurants. We initially weren’t PCI compliant but it didn’t matter because we always installed on the network that didn’t process credit card info. Just one potential customer asked us about this…

https://en.m.wikipedia.org/wiki/Payment_Card_Industry_Data_S...

I remember Target stores getting hacked a few years back and having a few million credit card numbers leaked..

https://money.cnn.com/2013/12/18/news/companies/target-credi...