Using Cashier's subscription table for offline payments?

Say I build and app, and I setup Cashier with Stripe and everything works fine but I also want to have an option for people making payments differently (say offline, by cheque).

Rather than building a separate system alongside Cashier, I'm thinking of "highjacking" Cashier's table. For example, I'm thinking I could set a subscription name, user_id, trials_ends_at, and ends_at "manually" in the app, without actually filling the other fields. That way I could have some other kind of payments, and still try and leverage Cashier's methods, or create my own, but not duplicate tables.

Is this a bad idea? (Probably.) But is it feasible? Doing so, would I break Cashier's regular utilisation?