It is the responsibility of the member to make sure he or she is on one church roll. If moving from one denomination to another, letters are not usually transferred or notice given to the old church by the gaining church. It is not fair to the old church to carry someone on their rolls that is active in another church. It is a waste of time and resources trying to restore such a person.
Whenever I have left a church (for whatever reason) they knew that I was. Sometimes, I transferred to another church by letter and sometimes not. It depended on why I left the previous church, and it wasn't always under good circumstances. One church I left because of the constant conflict and name-calling going on there.
Another church I left (after 20 years of faithful service) when the pastor's wife left him and divorced him. For 3 years I prayed with the pastor for his wife to return, but after that 3 years she divorced him. Then the bitterness and anger started, and he started verbally taking it out on me. I took it for a long time until I couldn't take any more and left. He had a master's degree in psychology and could make me feel guilty when I wasn't. He was a master manipulator, and I never knew that until his wife left and divorced him. Then his true character came out. I loved him like a brother, and we were very close. That is what made it hurt so much.