Report was that up until recently the kid was thinking of pulling out of the draft. You can bet that the reason he stayed in was because the Spurs guaranteed him they would pick him at 28 otherwise he would have withdrawn. You can bet since the Spurs guaranteed him they would pick him they had him rated higher than a lot of players taken ahead of him that might have potentially fallen to the 28th spot. We might be surprised at how high they rated him. Maybe they'll say someday.
People (reporters, scouts) knew that the Spurs were interested in a French player, probably from Presti, Buford, et als. scouting pattern. Some knew or suspected toward the end it was this kid probably because he was French, 18 and didn't pull his name from the draft. The biggest risk likley was some parasite like Thorn grabbing him before the Spurs pick.