The UCI regulations state that the penalty for an act of violence 'towards any other person' (i.e. non-riders) is elimination from the race plus a 200CHF fine, but Lopez avoided punishment from the race jury, who classified his outburst as a 'human reaction'. Lopez later apologised for his actions and asked for more respect from the fans. You can view a video of the incident below.
Lopez was leading a chase group behind the attacking trio of Vincenzo Nibali, Richard Carapaz and Mikel Landa at the time of the incident.
A man who was running alongside Lopez, Pavel Sivakov (Ineos), Bauke Mollema (Trek-Segafredo) and Domenico Pozzovivo (Bahrain-Merida) tangled with another fan and then ran into Lopez, sending the Colombian sprawling.
Lopez quickly got to his feet and swatted the fan in the face before knocking his cap off and returning to his bike to continue, eventually finishing 1:49 behind stage winner and teammate Pello Bilbao and the maglia rosa group.
"I got knocked the ground. This requires more respect for the riders. I’m sorry. It was a moment of pure adrenaline and it happened like that," Lopez said.
Spectators running alongside riders have caused a number of incidents in the past as their enthusiasm for cheering on the riders clouds their situation awareness. Nibali fractured a vertebra after being knocked down by a spectator in last year's Tour de France, and suggested the race organisers should look at adding more barriers.
"On climbs like that, with so many fans on the road, things can happen but they’ve come to see us," Nibali said. "The important thing is that everything is well organised and safe. It’s not hard to put barriers out on a six-kilometer climb. I don’t want to delve into the work of the Giro organisers because they look after a lot of things. But the riders are always asked for a lot, but we just ask for a little more protection.
"I’ve nothing against what Lopez did or what the fan did. Something similar happened to me last year at the Tour de France. I came off worse and it took me a long timer to recover and my back still sometimes gives me problems."
Lopez asked for more respect from the fans.
"It’s very unsafe. It’s happened a lot in the Giro, in the Tour, we deserve more respect," Lopez said. "I understand that there is a lot of emotion, but we are making huge efforts and then they come up and they knock you to the ground. What happens if you break something and have to go home?
"We wanted the victory today, and we got it with Pello. If for not what had happened, I would have been there, too. I had the legs to fight for the win. I lost a little, but I will give everything in the time trial. I will give it my best to try to bring the white jersey home."
Astana DS Giuseppe Martinelli was relieved that the jury let the incident pass without punishment.
"Some kind of punishment would be totally unfair after he was the one who was knocked down and lost time. If he’s punished it’d be the end of cycling as a sport," Martinelli told Cyclingnews. "I think it’s normal that he reacted as he did. He was on the way to winning the stage… I’m only sorry that he didn’t give the spectator some more punishment, he deserved it for what he did.
"Riders are supposed to respect the fans but the fans are supposed to respect the riders, too."
Astana manager Alexandre Vinokourov said the incident was not good for cycling, and called on spectators to be more cautious.
"After what has happened all Giro with bad luck with Lopez and now on this last climb the crash with the spectator. But sometimes you act like this with emotion and maybe he don’t do it like this but I’m so sorry for this for cycling it’s not good," Vinokourov said. "But maybe it’s a message for the spectator to be more careful in the road. It’s very – I said not good – imagine if you have the pink jersey, it’s more of a big problem. But we won the stage and it’s a great victory."
It's the latest in a string of unlucky moments for Lopez during the Giro d'Italia. Both the stage 9 time trial to San Marino and the stage 11's climb to the finish at Lago Serrù saw him lose time due to mechanical problems.