When Marty McFly intervened, he said no and resisted Griff and the gang. This led to a hoverboard chase around Courthouse Square very familiar to Old Biff Tannen. They trapped Marty over a manmade lake in front of the courthouse and they hooked onto Griff's Pit Bull hoverboard. Griff and the gang zoomed towards Marty but he jumped clear of Griff's bat and they hit the edge of the lake, flying into the courthouse's windows. The gang was then arrested for damages and Marty Jr. never went on that robbery.
In the opening sequence for the first season of the BttF Animated series, Marty is being chased by Griff with two completely different unnamed gang members five months before the infamous Hoverboard rampage. Canonocity, even within the context of the Animated Series is questionable.