You just reminded me of my first job (call center)
My shift officially started when I logged in and set my terminal to “available”
Problem was that the parking lot was very small so sometimes I had to wait for someone to leave to be able to park, then try to find an open computer close to my area and then sometimes said computer took a long time to log off/on so by the time I could set my terminal I was already “late”
My first manager was great and I would send him an SMS as soon as I walked to the building and he would override the system if I logged in late, but my second manager told me to arrive half an hour early to avoid any issues. I quit that job shortly after that