There are many well cited examples.

I believe in politically sensitive areas like Xinjiang it happens to everyone. A past employer gave specific advice regarding Hong Kong as well.

I think the key thing as a traveller isn’t the righteousness of China vs. US. It’s the chilling effect on travel and trade.

We really depend on these devices that have access to vast scopes of personal and other data. That sexy text you got a year ago is still in your text message store and may be a problem in some places.

If we're talking about targeted hacks, are we sure the US doesn't do this? Is US soil off limits for hacks somehow? What plausible exploits could be done when someone is on US soil, but not over the internet, especially on modern phones where the baseband is isolated?