Did it slightly different in my day. We paid them, whether we liked it or not.
I had no intention of purchasing my discharge when I was up in front of the flight commander for some minor infringement in January 1968. Never even entered my mind. I am quite sure that he raised it as a suggestion, and I must have nodded or something because next minute he had the application forms out of his desk drawer and ready to go. I was aware that it was considered insubordination if a person attempted to back out once it was being "discussed". So I was trapped. Two weeks later I was out, on the dole in Hull in the middle of Winter. Not a happy person at all.
Sometimes wonder whether he didn't have a "quota" of "redundancies" to meet. Wouldn't surprise me as I have heard of others being similarly disposed of about the same time.