News reports show up from time to time about people stealing grapes. Lots of grapes, like a vineyard full of grapes. An AP story recently appeared, telling the tale of thieves in Germany harvesting grapes that weren't theirs.
They came in the dead of night to Germany's Pfalz wine region and hand picked rows upon rows of Riesling, Trollinger and Grauburgunder grapes. This would be a huge financial loss any time, for any winery, but a late frost in May 2011 killed many grapes, so the ones that survived are the last hope for these winemakers. Add in the fact that the remaining grapes are thought to be of extremely high quality, and it's a double whammy. Also, most of these family-run wineries have no insurance that covers theft of grapes.
It's not unusual for harvesting to occur at night, so there would nothing overtly suspicious about seeing people with flashlights working the vines in overnight hours. Some witnesses claimed later they did see people in the vineyards, but simply thought it was the usual harvest.
Some winemakers in the region are now clinging to ice wine as their last chance to salvage something from this vintage. Grapes for ice wine are harvested when frozen, and the winemakers are keeping close watch on their vineyards until it's time to harvest them. They know, however, that the criminals are watching closely, too.