I have asked this question before, but never really got a satisfiable answer: why do governments (not just USA/canada) spend these resources to check data physically at a border? It's not like you need to 'smuggle' any form of data physically. I mean, any data considered to be dangerous (like terrorist attack plans, atomic bomb designs or political inside information) can be accessed across borders via the internet.…
So the actual reason customs agencies perform these searches is that they are allowed to do so because of the way the laws are written and precedent is set.