+ My communications with significant others which may be of various degrees of sfw
+ My work files, including proprietary or secret information
Any of those things would absolutely require a warrant, and may even require a specialized warrant in some cases (communications with my lawyer, health information).
This is a nuanced topic (border security), and while I think there's slippery slopes (and their associated fallacies) in both directions, it is true to say that you are very free to share none of those things with border security, and border security is very free to not admit you to the country.
In most countries, border security isn't entirely free to run rampant over your basic freedoms. Privileged communications (eg client/attorney) is an extremely important basic bastion of freedom and law, and violating that (which in this case seems incidental, not intentional) is a mockery.
Sure, any country is welcome to violate that norm, just the same as any country is welcome to force it's people in labor camps for insulting Dearest Leader. The rest of the world is also welcome to respond appropriately.
+ Communications with my lawyer
+ My private health information
+ My detailed financial information
+ My communications with significant others which may be of various degrees of sfw
+ My work files, including proprietary or secret information
Any of those things would absolutely require a warrant, and may even require a specialized warrant in some cases (communications with my lawyer, health information).