There are ways of dealing with this scenario. The simplest being, don't keep the information on the laptop. After entering the country, use VPN or some other secure means of downloading the data.
Rule number ONE of information security is that if you don't want it leaked online... DONT PUT IT ONLINE.
So your solution is not good enough.
You ask that I trade the physical security of an encrypted, air-gapped unit, physically in my hands with a solution that entails all kinds of possible network threats. MITM, SSL vulnerability, zero-day attacks, certificate compromises... and suggest this will improve my security??
No.
Not to mention that it assumes you're moving relatively small amounts of information between countries with good internet access... what if your destination just has shitty internet?
Plus if you legitimize their right to inspect all data at the border, then your just a hop and skip away from giving them the right to inspect your vpn traffic as it crosses the border; and they would be within their rights to demand the encryption keys from you or block your vpn connection. Some governments are already moving in this direction.
So your argument that "don't take it across the boder this way"... "take it across the border this other way" sort of falls completely on its face. Once you say "they can inspect and require you to decrypt data crossing the border" then your VPN is next.
but for most business related cases I would think this would be an acceptable workaround.
For most legitimate business related cases border security wouldn't really be a risk, even if you gave them the password, and let them fish around in your laptop. They wouldn't know what to do with it, or how to capitalize on it.
But its the principal of the thing; they really have no business being in there. And there is a chance they could learn or reveal something that is damaging.
Frankly, it seems to me the best solution right now; is to ship yourself the data by traceable courier. Small chance it is lost or confiscated at the border. But they don't get anything valuable if that happens, and you can't be arrested on the spot.