A smoke bomb tossed into the peloton about 16km from the finish of stage 13 on Friday threatened to cause another ugly incident at this year's Tour de France.
On a day when race director Christian Prudhomme called the behaviour of a small minority of cycling fans "immoral", and appealed for calm after the disgraceful scenes witnessed on Alpe d'Huez on Thursday, the atmosphere was generally far more subdued. The 35ºC heat and pan-flat stage might have had something to do with that.
Geraint Thomas - who sensationally won Thursday's stage to increase his overall lead to 1min 39sec over teammate Chris Froome - certainly had a more comfortable day in yellow. He negotiated the 169.5km stage from Bourg d'Oisans to Valence without losing any time as Peter Sagan (Bora-Hansgrohe) sprinted to victory.
It might have been very different, however, had a smoke bomb lobbed into the main bunch of riders towards the end of the day brought anyone down.The incident, captured on television, appeared to show bystanders on the right-hand side of the road wait until the main bunch was passing and then toss a missile casually into their midst.
It was unclear whether the person responsible was aiming for any rider or riders in particular. But given the reception Team Sky's riders have been afforded in France over the past few years, it would be reasonable to speculate it was intended for them.
On Thursday's stage a fan was arrested, allegedly for throwing a punch at four-time Tour champion Froome. The Briton was cleared just before the start of this Tour of any wrongdoing in his long-running salbutamol case.
Another spectator was caught on video shoving the British rider as he passed, while there were various reports that Team Sky's riders and vehicles were spat at on climbs.
Bahrain-Merida's Vincenzo Nibali, meanwhile, was forced to abandon the race after his handlebars got caught on the camera strap of a spectator. The Italian, one of the big race favourites, fractured a vertebra in the incident, which took place after a smoke grenade had gone off.
With Tour organisers ASO under increasing fire to protect the riders, Prudhomme addressed the matter at the start of Friday's stage. "The riders of the Tour, the champions of this race, need to be respected," Prudhomme told AFP. "I heard the whistles on Alpe d'Huez, just as I did in the Vendee [at Sky's team presentation at the start of the Tour]. On the roadside it's been calm for the past 10 days or so, with very few anti-Sky or anti-Froome banners. But suddenly, we've seen a lot more.
"All I can do is renew calls for calm, for serenity with regards to the riders on the Tour de France."
Friday's smoke bomb caused little distress. Thomas said he did not even notice it. "I didn't see it. I was totally in the zone at that point, going full gas," he said. Had it felled a rider, however, or caused anyone to swerve, it might have triggered a chain reaction.
Prudhomme added of smoke bombs: "Some fans have only one wish: to be on television and take a selfie. We don't want to see that again. Rocket flares don't belong in bike races. They make the riders breathe in noxious air and they blind them. It just doesn't make sense.
"The vast majority of the fans on the roadside are well-meaning, but [on Thursday], on the second half of the climb, the public were, at times, a little reckless.It's a paradox that Nibali, who has nothing to do with Team Sky, ended up on the tarmac."
Sagan, meanwhile, took his third victory of the race as he outsprinted Alexander Kristoff (UAE Team Emirates) and Arnaud Demare (Groupama-FDJ) in Valence. After three tough days in the Alps, the break was kept on a very tight leash by those teams who still have sprinters left in the race, which is not many.
Yesterday's stage saw the riders continue over to the Pyrenees with a run from Saint-Paul-Trois-Chateaux to Mende.
The last time a stage finished in Mende, in 2015, Briton Steve Cummings took victory for his South African team Dimension Data on Mandela Day. Froome had urine thrown at him...