What do they do if you say no in this situation though? Escort you home and inspect your desktop computer there? If I were to tell them that I carry a travel laptop/phone with no information on, there's little they'd be able to do about it unless that in itself was somehow made a crime.

You can be as honest as you like. Or just say you don't take data with you when you travel. For security reasons. If it's work related, this is trivial to justify: company policy, trade secrets shouldn't fall in the wrong hands, etc. And even if private, phone theft and identity theft are serious concerns.

I would hope that admitting to deleting data is not admitting to a crime. I delete data all the time (old emails, texts, pictures, etc...)

Say, "yes I wiped it in case it got lost whilst I was travelling"?

yes, I'm not importing that data to the USA?