Some scary people in this topic... But I had a rat problem and they were really making a lot of noise in my attic and chewing stuff. One family was actually not rats but just mice.... and they were cute and didn't actually do anything but since they were smaller they somehow managed to make it into my room and I caught them and saved two of them. One was a baby, very cute and very fast.... much smarter than the actual rats that were being annoying. Later on the mom came looking for the baby and I caught her too and let her go outside.
Later on.... A week later maybe....
A trap guy came in and I thought he was just using "normal" instant kill traps but he was actually using traps AND poison. The poison gets into their system and dehydrates them and they go blind and eventually suffer a horrible sad death. I didn't ask them to do that but it wasn't up to me. How anyone could enjoy watching it, is beyond me and you might as well be a different species than me if you can kill even a pest. I understand killing bugs... like ants that are around us by the thousands.... but they literally exist... then boom, they don't... But even "vermin" have brains... and have thoughts and fears.
I tried my best to actually save even the rats but they are dumb... and run from me. One rat managed to get into my bathroom and he was just lying there and I put him outside and he was stumbling around. I didn't know that he might have been poisoned at that time, I found out later. I even tried giving him some water and food but the guy told me he was probably already blind.
I think maybe there were only a handful of rats... there has not been any every since.... However in a situation like an actual infestation... I'm not sure what you can really do about it. It's just sad we put ourselves above another creature.... we both end up in the same place. Dead. Everything you do will be gone and forgotten just like that rat.