Why do you think I said it was nasty? But it's an idea I've had since before that series hit the airwaves -- it may even be somewhere in the archives.
It's worse for our hypothetical Racers because they have more of the illusions of being the whole group. Start them off at seven or less teams, and they will have suspicions of a second squad traveling somewhere: there's just too few of them. Begin at eleven on a side, cut down them down to five the normal way, and all should be well until they hit the uniting point. And since the criteria for picking All-Star teams is so
incomprehensible mysterious anyway, the 'Why isn't X here?' questioning session should stop during the first flight.
The biggest key to keeping the illusion going is Phil's physical presence at each Pit Stop. The Lairdroid could set things up because no one knew what to expect from him and doing nothing but appearing on a cell phone was his normal. As soon as Phil isn't there at the mat -- oops. Some Racers might question all the extended Pit Stops, but that can be dodged by having extremely active legs, one where they need a day and a half of rest before they can even think about rolling over in bed.
The double-show aspect would be fun, though. How goes things with Racers East? What's going to happen to that alliance with Racers West when they see their proposed Final Three now has five more teams to beat? Can Phil avoid being seen at that airport? Ooooh, drama...
There are other shows where this could be done -- Survivor may actually be the easiest, as long as the islands are outside casual rowing distance -- but the time extension would start becoming too much of a problem. And it's easier when we know the players already, regardless. Given that EPMB can't be bothered to introduce us to twenty people, I'd hate to see how he'd handle forty.