Should I be worried about this "WARNING CMDLINE SETTING MODIFIED?"

I was asked by the local police department if I would be willing to give them my phone so they could look at messages between myself and another person for an investigation. I agreed. When they gave my phone back there was the warning when I plugged it in to charge or turned it on. Just curious as to what exactly the warning means and if I should be concerned. Thank you.

Welcome to Android Central! Which phone?