The internet is a lovely source of information, but sometimes it just can't be trusted. According to this Wikipedia page the playoff between CONCACAF and CONMEBOL was supposed to be a one-game playoff and it was supposed to be played in Rio de Janiero, Brazil where the Olympics will take place.
However, today Sports Illustrated reported that the playoff between the United States U-23's and Colombia will in fact be two-legged home-and-away playoff series to be played during the March 21-29 FIFA international break.
Normally this would be good news for both teams. Who wouldn't want to hold an Olympic playoff match in their home country? Obviousl advantages would include a home-field advantage and an extra high profile match to make some money off of.
Unfortunately for U.S. Soccer, if the attendance numbers for the CONCACAF Olympic qualifying tournament are any indication of what we'll see for their home leg against Colombia, we'll benefit from neither a home-field crowd or a giant pay day for the federation. The type of attendance we saw at those matches were embarrassing. Official numbers haven't been released, but it doesn't take a mathematician to count 500 people in the stands.
The main factor in the low turnouts were the outrageous ticket prices CONCACAF charged for entry into the tournament. We've been told that American Outlaws members were charged $40 for one ticket in some cases. For a youth competition to have such a high price tag attached to the tickets is ridiculous. If the U.S. has any chance at anything resembling a home-field advantage against Colombia, this problem will need to be rectified by the decision makers.