https://www.chp.ca.gov/notify-chp/ch...tion-violators)
California highway patrol has a program for ca residents to tattle on their neighbors who have these out of state plates.
Don’t be surprised if this kinda thing comes to whatever shit hole over taxed/regulated state too.
As far as getting pulled over police probably won’t stop you for having a Montana plate, but they will not struggle to find a real reason to stop you if they suspect you are using this tax loop hole. Tint, no front plate, loud exhaust, driving like a BMW driver.
Once they stop you for a real reason and you have to hand over your license and registration is when they will learn you have Montana plates and a license that doesn’t match.