It’s not on 38% of phones. It’s on 38% of phones that they search, and they only do that in situations where they think they are likely to find something based on the story provided by the traveler. Usually it involves working on a tourist visa, or intent to overstay on a visa (person claims to be visiting but does not intend to leave).
I think I've mentioned it before on a story like this but if you watch the Border Security shows it's pretty obvious what most of the people they search end up being. Yeah it's a show but it's a pretty good slice of what they get.
