It's a bit easier for the consumer here in Germany, Cris. All type approved components have to be checked during the equivalent of the vehicle MOT. All relevant data is entered in the vehicle log-book so the inspector will check the details on the towbar manufacturer's plate or the information on the tyre walls, for example, against what's in the log book. If he fails to notice or if he does notice and is supplied with convincing proof that the non-type approved part is as good as or superior to the original fitment, he will OK it and it's his full responsibility and not the consumer's, even in the case of a later insurance claim (this doesn't apply to warranty, however). This procedure provides for non-standard fitment of components without the onus being on the owner. Of course, it does also mean that vehicle must be re-MOT'd and the log book amended accordingly when non-standard parts are later fitted. This includes installation of a towbar. That's why most people here who wish to tow, order their cars with a factory-fitted towbar (it'll then already be in the log book when it's first issued and the car doesn't have to be MOT'd when it's maybe only a few days old).