Yeah, there needs to be more secure bike parking. A reallocation of space from car parking to bike parking is an obvious solution. In Cambridge there is a bike parking facility that I would feel confident leaving a bike in for long periods but not every station has such a thing.

That being said, I know people who have done the two bikes thing, or at least one bike that "lives" at a railway station, for a long time and not aware of them having any problems.