On the other hand, a hard drive, EMP or not, will lose its **** after just a couple of years sitting on a shelf. I believe it's called bitflux. To retain the integrity of their data, hard discs need to be spun up and "refreshed' periodically. Google did a study a few years back and determined that after only 1 or 2 years without being powered up, hard discs ran a serious risk of data loss.
So much of production has gone tapeless now and the archival issue is one of the big concerns. Most serious post houses who know what they are doing are using LTO or DLT tape backup, with multiple copies (one stored offsite), but most in production seem to be unaware of the archival issue. A few months back I was dropping off some footage at a local production company that does their post in house. I asked what they were doing for archival of client projects. They just threw stuff on a hard drive and put it on a shelf in the closet. I asked them what they did to refresh the data and they were clueless. Not long ago they called about that footage again; they had needed to re-edit the project and low and behold their "backup" had corrupt data.