I used a very specific word for a very specific reason. That word was "spoliation". It is a legal word. It means destroying evidence but it means more than that.

If you're the subject of a lawful search and you destroy evidence rather than handing it over, that's spoliation. It has legal consequences. Courts are allowed to assume that whatever was destroyed was detrimental to you or your case. You can be charged with it as well. That's basically what happened here.

Consider this example: many companies have an email retention policy where emails will be automatically deleted after a period. I've heard of cases where this has been as little as 14 days. Typically though it's 1-5 years. One of the reasons companies do this is so discovery can't go and dredge up something really old in a lawsuit.

If this is a company policy then that's actually fine (ignoring any regulations or legislation tabout required retention).

Once you get subpoenaed you may get a hold on your email. The company is then required to retain it reagardless of this policy. If you then delete an email, that too is spoliation.

Do you see the difference? CBP can search your device. As soon as they request it, deleting the contents, regardless of what it contains is a crime. Wiping your phone before every border crossing as standard practice is not.