Former 100m world champion Collins believes suspension is punishment enough for athletes.
Britain’s Mo Farah survived a last-lap trip to retain his 10,000 metres world title in some style, extending his dominance of men’s distance running at major championships.
Almost tripped up by Kenya’s Geoffrey Kamworor as he took the first bend after the bell, the 32-year-old regained his balance and his composure to storm down the final straight and finish in 27 minutes 01.13 seconds.
Farah, who has endured a difficult few months after his coach was the subject of doping allegations, raised his arms and roared in delight as he crossed the line.
Kamworor was outpaced over the final 100 metres but finished second in 27.01.76 to claim silver, while his compatriot Paul Tanui was a distant third in 24.32.34.
His season has been overshadowed by allegations in a BBC investigation linking his coach Alberto Salazar with doping. Salazar, also the coach of American Galen Rupp who finished fifth on Saturday, denies any wrongdoing.
Earlier, Usain Bolt and Justin Gatlin moved a step closer to their highly anticipated Beijing showdown when both eased through the 100 metres heats.
American Gatlin underlined his dominance of the sprints this season by storming to victory in the sixth heat in 9.83 seconds, the best time of the day at the Bird’s Nest stadium.
World record holder Bolt, whose season has been disrupted by joint problems, responded by winning the final heat in 9.96, a time which ranked fifth behind Gatlin, American Trayvon Bromell (9.91), France’s Jimmy Vicaut (9.92) and Asafa Powell (9.95).