In Germany it is not allowed to transport unsecured animals either, even though the fines are comparably low (only up to 75 EUR). However, in case of an accident you would be uninsured and further, in a privat law suit following such an accident, this might be viewed as grossy negligent. I would also be afraid of my cats getting hurt if I have to break abruptly or - heaven forbid - have an accident. My dog travels in the securest crate I could get and my cats, on the very few occasions I have to take them, are crated as well (and hate it).
Another question, though, if you stop, even if only for fuel or a short "bio break", how do you prevent the cats slipping past you outside? For me this is sometimes difficult with only 2 cats and at home, as they seem to come out of nowhere and are between your feet and past in a blink. Or are your cats used to be taken out in a harness and wait for it to be fixed so they don't try to get out on their own?
Another question, though, if you stop, even if only for fuel or a short "bio break", how do you prevent the cats slipping past you outside? For me this is sometimes difficult with only 2 cats and at home, as they seem to come out of nowhere and are between your feet and past in a blink. Or are your cats used to be taken out in a harness and wait for it to be fixed so they don't try to get out on their own?