Your operator can neither see what software you're using for dial up nor can he detect that your stick has been unlocked.
There's absolutely no technical risk with debranding and unlocking. However the Tchibo-specific plugin for credit management ("Guthabenverwaltung") in Tchibo's version of Mobile Partner do not exist in the original unbranded Mobile Partner. Instead you will need to enter the USSD requests (codes like *101#) manually in the USSD plugin (see
Germany - Tchibo - Prepaid Wireless Internet Access for all codes).