Hello,
It's changing the ranking based on the fact that the driver is unsigned.
So when we find a match of the PNP ID's we then use the better ranked
driver based on the rating.
Since the driver was unsigned the ranking is lowered.
The inbox driver now ranks higher than the non-signed drivers so the inbox
driver gets installed.  
See also:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/DevInst_d/h
h/DevInst_d/install-over_806ed23a-ab2b-4891-bad1-33fc1dba7c13.xml.asp
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/DevInst_d/h
h/DevInst_d/install-over_276b1d55-635f-48c4-9f03-9e99426723df.xml.asp
You can override these settings while inside the OS.
The unattend setting allows you to install unsigned drivers, without
nofifications during setup.  But it doesn't change the ranking of how
drivers get installed during setup.
Thanks,
Darrell Gorter[MSFT]

This posting is provided "AS IS" with no warranties, and confers no rights
--------------------
<Newsgroups: microsoft.public.windowsxp.setup_deployment
<Subject: Re: Sysprep "prefers" Windows driver instead of mine ...
<From: Adam Leinss <aleinss@hotmail.com>
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<
<nicolas.gendron@gmail.com wrote in
<news:1156795164.882173.96010@i42g2000cwa.googlegroups.com:
<
<> Here are some informations :
<>
<> My [Unattended] section in sysprep.ini file looks like :
<>
<> [Unattended]
<> DriverSigningPolicy=Ignore
<> OemPnPDriversPath=drivers
<> OEMPreinstall=Yes
<> UpdateInstalledDrivers=Yes
<>
<> however, it seem that DriverSigningPolicy=Ignore line is being
<> ignore. In setupapi.log there is the line :
<>
<> #I087 Driver node not trusted, rank changed from 0x00000003 to
<> 0x00008003.
<
<Interesting.  You have me a bit stumped.
<
<I did look up the above error message via Google and found this from
<http://download.microsoft.com/download/e/b/a/eba1050f-a31d-436b-9281-
<92cdfeae4b45/SetupAPILog.doc:
<
<7.1.1.1.1.2    INF Cache Needs Updating
<
<SetupAPI logs the following messages during the finding-the-drivers
<stage of driver installation. These messages are associated with
<locating the modified blender.inf file.
<@ 20:41:06.656 #I382 "blender.PNF" migrate: INF may have been
<modified.
<@ 20:41:07.813 #V042 Opened INF "E:\WINDOWS\inf\blender.inf", PNF
<created (Languge = 0409).
<@ 20:41:07.829 #I022 Found "Blender_Hardware_ID" in E:\WINDOWS\inf
<\blender.inf; Device: "Blender_Device_Description
<"; Driver: "Blender_Driver_Description"; Provider:
<"Blender_Provider_Name"; Mfg: "Blender_Manufacturer_Name"; Section
<name: "Blender_install-section-name".
<@ 20:41:07.829 #I087 Driver node not trusted, rank changed from
<0x00000001 to 0x00008001.
<@ 20:41:07.829 #I023 Actual install section: Blender_install-section-
<name.NT]. Rank: 0x00008001. Driver date: 07/01/2003. Version:
<5.1.3604.0.
<
<In the previous example, the #I382 through #I023 messages indicate
<that the dates of the INF and PNF files do not match and that the INF
<file is unsigned. Due to the former condition, SetupAPI regenerates
<the PNF file. Due to the latter condition, SetupAPI changes the INF
<file’s rank to 0x00008001. (The date of the INF file is specified by
<its DriverVer directive.)
<If the log file contains a #I087 message for a signed INF file,
<perform the following steps:
<
<1.    If the INF file is not in the default system INF file directory,
<delete only the PNF file.
<2.    If the INF file is in the default system INF file directory, and
<its name is oem*.inf, delete the INF file and the PNF file.
<3.    Re-install the device.
<
<---------------------
<
<So based on all that gibberish, I don't think it's rejecting the
<driver, but it's just telling you the dates of the PNF and INF file
<don't match and it changes the file "rank" accordingly.  I have no
<idea though why it uses PNF files to cache INF files.
<
<I'm also not aware of any logs of sysprep action.
<
<Is using NewSID instead of Sysprep an option in this case?  Also, are
<you specifying -pnp for sysprep on the command line?  If you aren't
<do so and vice versa and see what the results are.
<
<Adam
<--
<Visit my PC Tech blog at www.leinss.com/blog
<