Doesn’t work if the old club doesn’t bother de-registering players.
I remember I went from Upper Hutt -> 4 different clubs -> Naenae. Naenae had trouble registering me. Turns out they couldn’t transfer me from Eastbourne because I wasn’t registered there (I had even played Chatham cup for them!), they ended up having to transfer me from Upper Hutt, my original club - none of my other clubs since bothered transferring me.