So when I tell the BDO that my itinerary and reasons for traveling are none of their business, will I still be allowed to go through PreCheck?

This program is as big a load of crock as the TSA's come up with recently. Be sniffed by a dog and interrogated like a fugitive, and maybe they'll let you into PreCheck. Or maybe, and I suspect this is far more likely, the BDO will be on the hunt for a terr'rist on that particular day, and half of those who slide into the PreCheck line will be sent for a resolution pat-down. Because, really, why would anyone fly into Atlanta unless they planned to blow the city up?