Reciprocate immediately.
You do know the same thing happens in the States, right?
Customs and Border Protection officers are allowed to search your phone (without requiring a warrant) at U.S. borders and international airports, including reviewing texts, photos, and social media (and not only on phones, but also computers and digital cameras). The only difference between US citizens and non-citizens is that for Citizens they can’t deny entry to U.S. citizens for refusing to unlock a device, but for non-citizens they can deny entry.
So, the Red Chinese are not doing anything we’re not doing. What’s funny is that several countries actually recommend that their citizens carry second phones without vital personal, business, financial information when traveling to the States.
Which makes it a tad funny reading this thread.