How do I judge whether an athlete is drafting?

Is the race draft-illegal? (World Triathlon rule 5.5 a) For age-groupers: super sprint, standard, middle and long distance triathlon are draft-illegal. Sprint can be either. Mixed relays are draft-legal.

In a draft-illegal race (rule 5.5 c):

• The bicycle draft zone is 12 m, measured from the leading edge of the front wheel of the rider ahead. Entering it is drafting, unless one of the exceptions below applies.
• An athlete may enter another's zone to overtake, but must be seen to be progressing through it, and has no more than 25 seconds to get through. Several consecutive unsuccessful attempts to overtake may be called as drafting.
• An athlete is passed when the other rider's front wheel is ahead. The passed athlete must keep dropping back out of the zone. Re-passing before leaving the zone, or staying in it beyond the time allowed, is a drafting violation.
• Allowed in the draft zone: for safety reasons; within 100 m before and after an aid station or transition; at an acute turn; and in course sections excluded by the Technical Delegate (narrow lanes, roadworks, detours, safety).
• Every athlete is entitled to any position they reach first without contact, but must leave reasonable space for others. An athlete approaching to take advantage of a draft bears responsibility for avoiding it, and athletes must reject others' attempts to draft off them.
• The vehicle draft zone is 35 m, and applies in draft-legal races too.

In a draft-legal race (rule 5.5 b): it is still forbidden to draft off a rider of a different gender, a rider on a different lap, or a motorbike or vehicle.

Discretion (rule 3.1 e and f): officials may penalise an infringement not listed in the rules if an unfair advantage was gained or danger was created intentionally. In exceptional circumstances, they may adjust penalties in line with the spirit of the rules. Officials may use electronic and other technology to gather evidence of infringements (rule 11.4).