Yes this is the whole $5-dollar-wrench XKCD thing.

"Ahah! I've won! The data has gone!! MUWAHAHAH! Take THAT border guards".... congrats you're still going to the same prison though.

If you've got something to hide (legitimately or not), don't take it across the border in the US or anywhere. Even then I am sure they'll either compel you to hand over your cloud passwords or again you end up going to the same prison for some other reason.