If you're going to be recorded for some prank beforehand, you have to be notified that you'll be on video for a prank, even though you don't know what prank it will be, in this case they are pranked for a few seconds beforehand, with the video camera being obviously seen a few moments after being pranked like in the passenger seat or something
MagicofRahat next time you do this prank you should make some audio tracks of phrases that sound like Bumblebee from the transformers movies and play them to answer some of the driver thru people