I heard Mike Golic once say that every single play in the NFL includes a hold, and if you watched each play in slow-motion, with the benefit of replay, you could call holding on pretty much every play.
I think the same could probably be said of basketball with travelling. Maybe not quite as egregious as holding in football, but there's no doubt that it happens a lot, though I think it most commonly happens in low-pressure situations where it isn't happening in such a way that the offense gains an advantage, or as a result of defensive pressure (for example, a point guard walking the ball up to half court).