Pro decks either dispense with SCMS entirely, or provide some means to defeat it. There's no reason for professionals to have to put up with SCMS, since pros often need to make copies of their own music. Put the cover back on and you're done. Don't overlook the fact that DATs are compatible with many hard disk recording systems. If you don't have two DATs to make backups, you can copy the data from the DAT to the hard disk recorder, then load in a second DAT tape and bounce the hard disk data to it.
Many pros keep two backups.
On the next backup, the older backup is updated. Protect the current backup and unprotect the older backup so that the next time you back up, there won't be any mistaking which tape should be backed up to. Although DAT's 48 khz sampling frequency theoretically gives better high frequency response than 44.1 khz, the real world difference is negligible. Granted 99.9 percent of the time you'll want to avoid overload like the plague. But on tunes where extremely short percussive transients are the reasons for the overload, they can be slightly clipped.