I don't necessarily see this as a bad move for the Nets. They get some cash for putting an ad on a jersey not generally seen outside the PF.
I have very little idea why a flash-drive manufacturer would think that having their name on the practice jerseys, the coaches' post-practice apparel (how many post-practice news conferences are televised? Our "coaches' corner?"), or the PF itself would be a good use of advertising budget. Or the correlation between NBA practice and flash-drives.