I have heard a similar story as well. In northern Indiana, North Judson to be exact, there is a large mint crop, and supposedly they were brought in to eat the aphids that were damaging the mint crop. Whether or not that story is true, I cannot say. I can tell you that there are often many more ladybugs in the North Judson area than in the surrounding areas. I suppose that's anecdotal evidence at best, but the difference in bugs across a 40 mile drive is big.
My farmer friends tell me the orange "lady-bugs" are actually "bean beetles" and are trying to break into your nice warm house since winter is coming. They were introduced to control aphods, now they're a pest. Ain't it great when man decides to play with "Mother Nature"? We tend to always screw it up! They will last inside all year around, definitely pests!