Veritas uses MTF (Microsoft Tape Format) to write to tape.
If a password was not placed on the tape, any installation of BackupExec (or any other backup system that uses MTF- includeing NTBackup) would be able to read that tape, if SW compression was used NTBackup and Arcserve would not be able to read them, but any other BackupExec installation should be able to.
IF HW compression was used, any compatible drive would be able to read the tape