Certainly not, these camps are quite useful a week before the tie..
In fact they have been a most important segment of a DC tie preparation and the successes which we have achieved.
It has been our tradition from Krishnan,Amritraj,Naresh Kumar times to assemble at least one week before the tie and sometimes during that period the Captains have even called foreign Coaches or Players to give the preparation an extra edge, like during the 87 campaign, we had a guy Gene Halin for the entire year, and the most famous one of them was in 93, when facing the Swiss (Finalist in 92)at South Club club, knowing our players would be unprepared to face the tall Isner type Marc Rossets and Jakob Hlasek thunderbolts, Naresh specifically got in 6.5" Briton Chris Bailey to aclamatise and help Ramesh and Paes for the big serves, and what a master stroke from Naresh it was , as not only got Ramesh/LP better prepared but they even managed to cause a huge upset and went on to beat the Swiss, who incidentally were 92 beaten finalist.
Only difference here is that Mahesh has given these preparatory players meetings a different name, as that of a CAMP,
Moreover this Camp is starting on a Sat/ Sun, 5 -6 days before the tie and there could have been a possibility that Yuki would not have been engaged long enough till Sunday in Chicago and could have joined the team in time , And even if he was engaged he could have well joined the camp a day or 2 late as in case of Ramesh who could never make it in time exactly a week before as he was always involved in pre DC centric tournaments.
So it might have been very useful and ideal preparation for Yuki and also to Team India if he could have played Chicago and joined the camp in Belgrade once whenever he was done in Chicago.