"... searches don't just involve agents skimming through your contact lists or photos—the border police can use software to rapidly dump the contents of your phone, and download your full history from every social media site you use."
Companies that have maneuvered billions of people into storing their most personal information on their servers, and worked aggressively to insert themselves into every facet of social and family life, owe it to their users to fight, and fight hard, for their safety.
No they don’t, and they won’t. The profit motive is too strong.
Let’s be clear. The person on social media is the product. The product serves the needs of its users, the advertisers. This’ll be clear to anyone who’s run a paid ad on social media or seen a social media analytics dashboard. Complying with authorities either on data requests at the borders or otherwise is but a risk-return decision: will compliance with such orders result in enough people leaving to hurt profits significantly? Is building a ‘travel mode’ for social media accounts that locks sensitive data away from border agents worth the trouble with governments? The answer in each case is almost always no.
So. Expect nothing from companies you entrust your data with, beyond the service itself. In general, own your data and make your decisions on where to store your data, what to carry and how to conceal or encrypt it. There are no easy answers, and social media/cloud storage companies are certainly not going to provide any.