Credit goes to MeonOne for the image. There are 28 open world events, 17 of which are drug busts (aka security cameras) and will appear on your map once you complete the date with Not Ping. The other 11 are broken down into 3 categories:
Shoplifters (yellow)
Junk in the Trunk (orange)
Hit and run (red)
The most important thing to note is that the shoplift events happen at different times of the day, so if you are missing an event, hang out by the one of the 4 yellow markers so that the time of day changes (you will see the shadows shift).