Can you rephrase the question? What are you wondering?

How useful is it to clean all my work data every time before crossing the border? And if I'm asked why there's no data on my system, should I say I wiped it clean? or that it's a new system? or that it's a personal system?

If you find yourself in the position of answering why there's no data on the system, I think you'd already know the answer.

It takes a pretty invasive search to come to that conclusion. (Unless your definition of wipe is like, cat /dev/zero >/dev/sda, in which case they'd probably ask why it doesn't work pretty shortly after asking you to turn it on, and then you'd get to the conclusion fairly quickly.)

I've never had to deal with an invasive search like this but I've also never gone through customs with a laptop, at all. I think this kind of policy instruction is more useful as a way of simplifying the kinds of questions that General Counsel has to answer, especially in a corporate environment where you have a lot of (nerds) extremely privacy-conscious developers.

That eliminates a whole class of questions. "What should I do if I am asked to unlock my computer by a customs agent?" Let them search anything they want to, if they have legal authority to do it. "What if I have sensitive company data on my work laptop and we've signed XYZ NDA with LMNO Company?" This question and a whole host of related questions will never come up at all if there is a policy against carrying any type of sensitive data through customs.

If you are an employee of such company and you have issues with this policy, there is a pretty good chance it's because you aren't in the habit of keeping great backups. So that's one more great reason for the company to have this policy, as that's information that you'll want to become known and have addressed some time well before it matters.