Should we randomly go into people's homes and demand people to open up their houses and kick them out pending investigation? Clearly, we can do that now if they are 100 miles from the border if we can confiscate laptops and hold it then we can confiscate homes and cars and hold them for investigation as well.
Not exactly. You aren't considering that there's a threshold to overcome. All customs searches would be unreasonable if there were a trivial way to send items without going through customs.
Invading everyone's privacy to catch a few dumb criminals (because all non-dumb criminals would have just sent their data through the internet) is a really really bad tradeoff, because the cost:benefit ratio is too high.
