Well, considering that the only person I personally know ever to get sent back at the border was riding a Greyhound bus and was one of maybe three American citizens on a bus full of Mexican workers, and he got sent back because he didn't have $600 or a credit card on him (at least, according to the Greyhound people), unless your stories involve cavity searches, they probably can't be that much worse.

Note: this was in Seattle on the way to Vancouver, and while the bus driver, also an American citizen, was a total ass and confiscated this person's return ticket then claimed he'd never seen it, the OTHER Greyhound people were very nice and arranged for the trip back home.