Even if there are questions in [restore] that are not related to backups, the tag excerpt is unambiguous: (Actually, I interpreted the tag dates wrong. The tag has been around for five years, but the tag wiki was only applied in 2012.)
This has been the description of restore for the last three years:
Returning data from a backup to its original location or to its successor.
I'm inclined to say that the intended use of this tag has been unambiguous for the majority of its lifetime, barring the usual case where someone types restore whatever into the list of tags. Aliasing the tag to backup-restoration seems to make sense and would prevent further creep of unintended usage.