Maybe I'm not understanding something but when you say 4 TVs together - do you mean all 4 on the same wall in the same room?
How is that in anyway a 'simple set up'? How would you think there would be any other way to control something like that, unless you used some type of control system?

For the other customer; the LG OLEDs come with Bluetooth remotes. Did he plug all 3 TVs in at the same time while he was pairing remotes? Or did he not pair any of the remotes yet and it is responding to IR from an unpaired remote? My memory is failing me at this moment about how those silly LG remotes work.