Yes and you have to keep in mind that just because someone has the legal authority to seize your posession, you have no reason to trust that what they will do with it will be legal as well. For all you know they can do any number of stupid and/or malicious things with your device that don't reflect the intentions of the government they represent either (being generous here). They are just people, after all.

If you run a startup with millions of users it is reckless to assume you will not be the target of industrial espionage when crossing a foreign border or traveling in a foreign state.

> I still wipe my phone and restore from iCloud after I've made my way through customs or border control.

It's not enough to just re-install the OS. You have to have your hardware recycled (discarded). Within a couple of seconds, they can put spyware onto your firmware by simply inserting a prepared USB device. The only way to get rid of that kind of spyware is to destroy the hardware.

The other solution is to not travel to any totalitarian countries or to travel there without any hardware, if you must.

if its in icloud, they don't need to take your phone...

I don't think border agents take phones because they need to.