In the countdown to Friday's opening ceremony, a sprawling shopping mall next to the Olympic Park was briefly evacuated due to a fire alarm, officials at the Aquatics Centre were cranking up the air conditioning to bring down the heat for swimmers, and doping cost two more athletes their Olympic dream.
That all came a day after the North Korean women's soccer team refused to take the pitch for just over an hour for its match with Colombia in Glasgow because organizers accidentally displayed the South Korean flag alongside players' names on a giant screen during introductions.
Romney, who managed the Salt Lake City Games in 2002, caused a stir by telling NBC news, "It's hard to know just how well it will turn out." He described concerns over security staffing as "disconcerting."
Cameron responded by saying Britain is hosting the Olympics "in one of the busiest, most active, bustling cities anywhere in the world. Of course it's easier if you hold an Olympic Games in the middle of nowhere."
His comment apparently referred to Utah, the site of the Games Romney managed. The Times newspaper in London called Cameron's words an "Olympic putdown to Romney."
London Mayor Boris Johnson later told tens of thousands gathered in Hyde Park to see the Olympic flame: "There's a guy called Mitt Romney who wants to know if we are ready. Are we ready? Yes we are!"
Amid the uproar, Romney tried to back off his critique, finally concluding, "I expect the Games to be highly successful."
Olympic preparations are never flawless. Even Jamaican sprinter Usain Bolt admitted a stiff back has caused him hamstring problems recently, but he expects to be ready to defend his Olympic titles. Bolt set world records in winning the 100 and 200 metres at Beijing in 2008 and helped the Jamaican team set a world record in the 4x100 relay for a third gold medal.
But he lost to training partner Yohan Blake at the recent Jamaican trials and comes into London under a slight fitness cloud.
Stiff back or not, Bolt will be carrying Jamaica's flag at the opening ceremony.
In a flag issue of a different kind, the fallout continued from the flag flap of Wednesday night, with North Korea's IOC member Chang Ung saying it should not have happened.
Cameron described the mix-up an "honest mistake" and said "every effort will be taken to make sure this won't happen again."
IOC President Jacques Rogge echoed Cameron, saying it was a "most unfortunate incident" and "a simple human mistake."
Soccer was again the only sports action Thursday, with the first men's matches, including the long-awaited major tournament debut of Welsh veteran Ryan Giggs in the Britain team against Senegal at Manchester United's Old Trafford stadium.
The 38-year-old Britain captain has won 12 Premier League titles, five FA Cups and two Champions League trophies with United and earned 64 caps for Wales, but never qualified for a major international tournament.
Giggs looked like he would lead Britain to a victory until Moussa Konate's late equalizer cancelled out Craig Bellamy's first-half strike — set up by Giggs — to earn a 1-1 draw.
"I'm very proud to have been selected and very proud to captain the team," Giggs said. "Unfortunately, I couldn't lead them to a win today."
In early games, Japan beat Spain 1-0, denting Spanish hopes that its under-23 team could add Olympic gold to the senior team's World and European titles.
Gold medal favourite Brazil made no such mistake, rushing to a 3-0 lead over Egypt in the first half and weathering a come back to win 3-2.
With the opening ceremony just a day away, the Olympic torch was visiting the top tourist sites of London including the Houses of Parliament, Downing Street and Buckingham Palace, where it was do be greeted by Prince William and his wife Kate, Duchess of Cambridge.
The flame's 12,900-kilometre journey ends Friday night when the final torchbearer — whose identity remains a closely guarded secret — lights the Olympic cauldron.
Security contractor G4S said Thursday it is getting hundreds more workers each day who can hopefully replace British troops drafted in to cover a shortfall of guards.
G4S faced harsh criticism for failing to provide enough security personnel for the Games — a shortfall that forced Britain's military to deploy 1,200 more troops this week and 3,500 others last week.
Doping also claimed more victims Thursday, with the Court of Appeal for Sport upholding a two-year ban for Hungarian discus thrower Zoltan Kovago for refusing to provide a sample to officials last year.
Also, the father and coach of world indoor high jump champion Dimitris Chondrokoukis said his son has tested positive and withdrawn from the Olympics.
While doping and terror fears have been high on the list of concerns ahead of the Games, a sunny British summer has bathed the Olympics, much to the surprise of many Brits used to damp, cool conditions.
But as London bathes in sunshine, swimming coaches have complained that it is getting too hot in the Aquatics Centre.
Organizers said they are working with the air conditioning units to get the pool deck temperature down to 27 degrees.