The idea that members of the mainstream news media can negatively affect viewer perception by sharing a barrage of information with the potential to mislead or confuse viewers. ("Drive-by" comes from the term "drive-by shooting," in which someone riding in a vehicle begins firing a gun at an unsuspecting person on the street.) Popularized by US radio personality Rush Limbaugh. That reporter always seems to cause confusion and sow discord whenever she opens her mouth—it's drive-by media at its finest!
See also: media
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.