My DS will go to a primary school in 2012. When I go to work by train, occasionally I see some mums with a school child on the train, presumably going to a school near mums work. I wonder if it is worth trying to apply for primaries around work area, or is it completely unlikely to get a place due to distance? It would save me on childcare quite a bit and I would see my child more, so that would be quite an attractive idea..
I think (but experts will correct me if I'm wrong) that if they have a spare place then they have to accept your child. If they are full or oversubscribed then places willbe given on distance so your child would almost certainly not get the place (and be at the bottom of the waiting list). I would have thought city schools would be more over-subscibed so you could have problems with all but the worst, least popular schools.
Other things to consider are that your child would be living far away from their school friends, and also if you were to change jobs, what would you do about your school then? would you look to move schools to one locally to your home? This would be harder than finding a reception place during the usual admissions process.
Oggy is right - the chances of getting a school out of your area are very low if the school is popular and has lots of applicants. If for any reason though it has spare places then you can get a place. Oggy is also right about the pitfalls though.
The reason you might see children with their parents on the train is that once you apply and get a place, it isn't always easy to move schools (if all other schools are full) so if they lived in one town in Reception and then moved house, they may still be travelling to the school that was near their old house. Or they may be going to private schools which have no catchments. Or they may be going to a school far from home that just happens not to be filled each year with local children.