I went to the YouTube video and looked at all the comments. The most believable ones are:
1. At KSFB the taxiways are wide enough that the flight school planes are often cleared to taxi in opposite directions on the same taxiway, using the centerline as a divider.
2. This particular Cirrus contained a Flight Instructor who is no longer employed by the school.
3. It is unknown whether the Cirrus actually had taxi clearance, but suspect he was just operating from rote. Time was 11pm local.