The real problem here is downloading of data from the phone. Once that data is off-loaded, the government can make it a part of their "Seven-degrees-of-Kevin-Bacon-Osama-Bin-Laden edition" game, stored forever, perpetually looking for "connections" no matter how remote. That's a scary and slippery slope to surveillance state hell. I don't think such practices are commonplace, not yet?
Has anyone here ever been in a situation where the CBP confiscated their phone/laptop or downloaded data electronically from it?