[kaspiCZ]

They will most likely detain you. And grill you for quite some time.

Then seize your electronics, because "you have no need for devices you cannot unlock" (fictional quote) and most importantly you cannot prove they're safe (forget about them having to prove they're not safe).

And finally, they would most likely deny you entry.

Given that lately I've read hundreds of comments on US Customs here on HN, this is the picture I've painted in my mind.