False positive in tar detection

[DaleStan]

When I call ArchiveFactory.IsArchive with the attached file (which started life as a SQL CE database), it incorrectly reports that it's a tar file.

Is it possible to make the detection code stricter, or have I just stumbled across a pathological case?
false positive.tar.txt

[adamhathcock]

You might have stumbled on something because the file gets read and looks for a tar header.