Notice that none of the racers hailing cabs at the airport have their large backpacks with them - just small daypacks.
Compare that with the decoys in Vegas - they had their full backpacks with them.
Where are their bags? Still at the baggage claim?
My hypothesis is that the 3 decoy teams left Prague around noon Thursdayaugust 6, so they reached Las Vegas as follows:
OK650 Prague (PRG) - London (LHR) 1235 1345 connecting in Heathrow with
BA275 London (LHR) - Las Vegas (LAS) 1535 1825
That way they are well rested for the final race day and their bags have been long stowed in a hotel long before the Final 3 ever arrive in Las Vegas. If they need some bags for appearance sake, they bring those along.