Yeah. We bought an old Elantra which only came with a single key and no FOB. I bought a cheap gizmo on Amazon that you plug to the OBD port and allows you to program other FOBs.
Modern-ish cars are computers. Once you have physical access, all bets are off.
However, this is by no means secure where the car's ECU will happily dump its entire storage (including the SKC code) over the diagnostics port if you ask nicely.
Also, I have quite a problem with dumping entire storage (EEPROM parts for example, that contain SKC/PIN). Also, my experiance is that getting that info from modern ECUs is not that straightforward/there aren't many (in some cases any) tools to get it.
This tool successfully recovers SKC codes from pretty much any VAG Group’s (Volkswagen, Audi, Seat, Skoda) cars. It can also do other things like edit the odometer and probably more. It’s simply using “undocumented” (although is anything there documented?) commands of the diagnostics protocol to get raw access to the persistent storage.