My first and only paid subscription on one product I built was from a user who never used the service, and also never cancelled their subscription. It had no free trial, so they knew they were paying money from the get go. After a while I cancelled their subscription and sent them an email saying they could re-enable if they wanted to keep using the service. I felt bad for taking their money.

It was definitely motivating and I would say it was part of the reason I kept working on it, but unfortunately no-one else subscribed, and it wasn't to be.