Whaat! This one is new. You mean subscriptions from your neighborhood store such as milk, bread, newspapers, etc?
Even in the cases where you're allowed to cancel on the last day of the subscription, we as humans are very prone to forget to do that, particularly for longer-term contracts. Tracking contracts and subscription deadlines is a damn profitable habit that I wish I had acquired much earlier.
Not sure about credit damage, but in case of a loss in such a suit, I'd also have to cover the expenses for the other side, so it's a risky proposition.
With my wife we did consider it for a while, but then decided it's better to do focus on solving that problem with software and thus started working on contrax.app (shameless plug!).