Georgia rolls out a red carpet for them at the Masters Golf Tournament. Kentucky gets them tickets to the Kentucky Derby. Arkansas takes them on a private duck hunt with the governor. Utah recently arranged a private ski trip with an Olympic medalist.

Such is the life of site selectors—consultants who jet around the country helping corporations decide where to build new headquarters, factories or expansion projects, often pitting communities against each other in multistate bidding wars to maximize tax breaks, grants, land...