SafeDisc v4.60 on DVD - no weak sectors?

[hineck]

Hello everyone.
I am currently checking the condition of my (original) game collection and have just stumbled upon Quake 4 on a DVD. Protection ID reports "Disc Protection: SafeDisc Signature v 4 (or higher)" and the protection on the exe file as "Safedisc v4.60.000 detected !".
Normally SafeDisc has weak sectors that causes a surface scan of the media to show damaged/bad sectors, but the Quake 4 DVD has no bad/weak sectors as far as I can tell - Nero CdSpeed 4.7 reports 100% good sectors in ScanDisc. Just before I was scanning a copy of Need for Speed Underground 2 which reported several bad/damaged sectors in ScanDisc, and although that game is on a CD it also has SafeDisc (v4.8 to be exact)
Can it really be the case that there are no weak sectors present on SafeDisc DVDs - as opposed to CDs?

[Blazkowicz]

DVDs don't have weak sectors.

[hineck]

DVDs don't have weak sectors

Okey good to know. What constitutes the SafeDisc protection on DVD then?

[Terramex]

For once, I sort of disagree with Blazkowicz

The characteristic feature of the so called weak sectors on CD is that they can be read relatively easy, but depending on the Safedisc version writing is very hard right up to impossible.

Similar scenario with Safedisc on DVD with the difference that it's always impossible to burn a working backup without emulation.
There are three ranges of regular bit patterns with 16 sectors each which become erroneous on a backup DVD.

Don't know if there ever was an agreement on the naming, but at least in their sector viewer Alcohol Soft calls them weak sectors:

[Blazkowicz]

They are just not noticed during grabbing.