The Protecting Data at the Border Act would protect US citizens from arbitrary searches of their digital devices or service accounts as they enter the US.

Human rights apply to foreigners, too. I think foreigners should have a way to ask, before they buy tickets, whether the US would demand to investigate them in any of those intrusive ways. If the US says at that time that it has no wish to do search, then that foreigner would be treated at the border like a US citizen: searching per devices or accounts would require a warrant. If the US says at that time that it might search devices an accounts, it is not too late for that foreigner to decide to stay away.