It can be a bit complicated, but for starters, I understand there would be a right of burial at a parish church for (a) parishioners, (b) those who died in the parish, and (c) those who were to be buried in an existing family grave or vault etc.
You couldn't normally ask to be buried at a neighbouring church on a whim, and the provision for those who died in the parish would probably be taken to apply to those who died a long way from home. So if someone was buried in the neighbouring parish to where they were baptised, it's fairly likely that they had permanently moved there.
Others may wish to comment on this; there's also the question of what is a parishioner.