Several bike riders compete in a competition .
It is impossible that bike riders hold an illegal rally to block traffic on the busiest travel holiday of the year .
It is impossible that bike riders hold an illegal rally to block traffic on the busiest travel holiday of the year .
It is likely that bike riders hold an illegal rally to block traffic on the busiest travel holiday of the year .
Bike riders hold an illegal rally to block traffic on the busiest travel holiday of the year .