No, it’s not: it’s a fine you pay because it’s assumed you’ll litter some bottles: not all bottles have Pfand, which is nonsense: soda yes, juice not.
And the number of bottles lying around? Germans come back from Spain praising how clean the streets are and Spain has no Pfand system. That’s just not true.
Absolutely! Take care of your earth! But you don’t need to fine people for a loitering crime they haven’t committed. Not all bottles have Pfand in Germany: soft drinks? Yes, juice? No, beer? Yes, wine? No. It’s a hypocritical bullshit system.