Without knowing how many cameras they want to install it is hard to know the cost and potential problems. The DVR's hold more and more memory for less money. It is not that hard to have a DVR that would hold for a period of 30 days. If you are talking about permanent storage that is different issue. But I would think it would record for some many days and if nothing major was reported it would erase and be recorded over again.
If installed high enough I think they would be safe from vandalism. There are already cameras there.