Pets are considered property in the US much like a car, that is like if you take your car to be fixed you don't get it back until the bill is paid. You can prosecute people using Theft of Services, but it is legal to hold onto the pet (collateral) until the bill is paid.
I'm not saying it's ok for people to not pay their bills, but surely pet owners have some rights to stop people taking their pets? A pet isn't like a tv/computer/whatever else, it's a living thing.. As far as I know, at least here in the UK if you have debt and have bailiffs came to take things for example, they can't take pet's (I might be wrong, but I'm sure I read/heard that somewhe