I will gladly help you supplement your historical knowledge. It seems to be incomplete.... :)
The Deutsche Volksliste categorised Poles into one of four categories:
* Category I: Volksdeutsche-Persons of German descent who had engaged themselves in favour of the Reich before 1939.
* Category II: Deutschstämmige-Persons of German descent who had remained passive.
* Category III: Eingedeutschte-autochtonic persons considered by Nazis as partly Polonized (mainly Silesians and Kashubs); refusal to join this list could lead to deportation to a concentration camp
* Category IV: Rückgedeutschte-Persons of Polish nationality considered "racially valuable", supportive of the Reich (e.g., collaborators)
Let`s look how it was done in Silesia region:
The remaining population of the interwar Silesian Voivodeship was inscribed onto the Deutsche Volksliste (DVL, German National List). The DVL's groups I and II contained 300 thousand persons of indubitable Germanness and the groups III and IV one million potential Germans. Berlin extended full citizenship only to the members of the groups I and II. The rest were mere state-members. But as Staatsanagehörige they could not be drafted into the Wehrmacht. With the opening of the eastern front in 1941 the need for soldiers became so acute that the group III (comprising about 940 thousand persons) were granted with Reichsbürgerschaft (Boda-Krężel, 1978: 13-20).
In general 300-400.000 people were conscripted by Wehrmacht in Upper Silesia, which contained a high number of German minority, ,many against their will by either forcing them to sign Volskdeutsche lists or signing them on them without their agreement.
Names very often appeared on the Volksliste without the consent of the owner. Very often fear promoted people to sign and often, given the harsh terms of the Nazi occupation, the promise of better conditions were enough incentive for people to sign up. Franciszek Janikowski was a Pomeranian who had been conscripted to the German Army before joining the Polish 1st Armoured Division. His appearance on the Volksliste was typical:
"My father worked on the railways. He had no land and no fortune so he was afraid. When they took them away in 1942 and asked who doesn't want to be Germanised? Nobody answered. My father signed and, as he told me later, he thought: I have a son ..."
I would really like to see some stats and links to that often repeated statement.
Polish deserters from Wehrmacht who joined Polish Army were estimated at 83.000.
Out of those 60.000 were from Upper Silesia.
Links to above info are here, unfortunately some are in Polish, but there is also one in German.
A site about Polish Armed Forces in the West
angelfire.com/ok2/polisharmy/chapter3.html
The hostages of war - a magazine article
"I didn`t want to go to that army" - memories of Silesians forcefully drafted into Wehrmacht
alfa.com.pl/slask/200501/s10.html
The historical forum, the thread`s title is Poles in German Army.
odkrywca-online.pl/pokaz_watek.php?id=385407
Polen in Wehrmacht, a site in German
www1.ku-eichstaett.de/ZIMOS/forum/docs/kochan.htm
An article entitled DUAL CITIZENSHIP IN OPOLE SILESIA IN THE CONTEXT OF EUROPEAN INTEGRATION