I hate to say, I told you so, but....
So many people back up the AC file to a thumb drive and take it home. It is significantly easier to lose than an external drive.
You are much better off getting a safe that goes in the ground. You would be more likely to put your backups there as well.
You could also put it on you smartphone with the ability to wipe the data, although this is less than ideal.
I have researched quite a few flash drives, and IronKey still seems to be the best solution. I still don't know why none of the solutions is based on only being able to use the same USB port on one computer.
As to your backup files, I would be careful what folder or path you store them on. If your path is \\server\Amazing Charts\AC.enc changing that file to an .xml file will give the path, therefore the holder of the file will now know to possibly download AC to restore the data.
