My view is while folks are rightfully pissed off being billed for damage; that alone is not proof of a scam operation especially whether Enterprise/Sixt also check their damage with similar degrees of standard. You can argue the entire German car rental industry as a whole is rotten to the core but IMO there's simply not enough data points to say this is systematic.

Furthermore the data set is inherently bias to begin with as in they are only from the perspective of the renter and pretty much only when renter received a damage bill. How many FT reports do we have where renter did cause damage and the agency didn't bill them? Or FT report documenting renter did caused damage and car rental agency did bill them (I'm guilty of not reporting this on FT)? Or reporting on FT a damage claim was dropped? A consumer is more likely to report a disservice than excellence in service.

IME in Germany, I've had about 120 rental days (30 rentals) divided between Sixt and Hertz and 1 with Enterprise. Out of the 30 rentals, I probably had to amend the condition report in less than 5 rentals before leaving the lot and the Hertz/Sixt agent were more than willing to update the report. Only three rentals involved a damage bill. One I did cause damage, another had a tire slashed which could have been preexisting (dim garage lighting) or could have been vandalism while I had the vehicle. Both were resolved by credit card insurance. The remaining one was concealed preexisting damage which could not be be checked prior to leaving the lot (rim bent on the axle facing side) but Sixt ultimately dropped the claim after a brief note. Based on my experience, I'm not seeing a scam. Can Hertz/Sixt bill these damages to the next renter despite the claim against me being resolved? Sure, but there is no proof this is happening.

I think many of the damage reports in this thread and Sixt thread could have all been avoided if renter had check/document damage before leaving the lot. Having to check the car for damages before driving off is a very different experience than renting from US (major agencies). Just because a renter flew in from another continent 10+ hours in time zone differences away does not absolve renter from doing a walk around of the vehicle; it's for their own protection. This is how Germany operates.

While there are a couple of damage reports throughout the years where rental agency could have been scamming due to the long delay between rental ending and damage report being generated but those are in the minority. Nonetheless while I'm keeping an open mind a scam could be happening but I don't think the available data is conclusive proof it is happening.