Can a cop still fine you when they have never pulled you over?

(This was in CA btw) I was dropping off my friend at a bus stop on a main street. I figured it would be a quick procedure. I turned on my emergency button and proceeded to drop my friend off, but then I looked behind me and a police car was there. The cop then said, “I almost hit you. You can’t park here.” I then rolled down my window and said, “Sorry!” and left. The cop never pulled me over, but I’m wondering, since the cop probably has my license plate number, can they still fine me? Or should I just take this as a lucky warning?