Readgeoff,
The usual problem with (very) low hours pilots is that owners tend to have insurance policies that specify minimum hours. In general, to fly their machine, you either need to have your own insurance (which generally blows the cost savings out of the water) or be put on the owners (which usually doesn't add any cost, assuming you meet the requirements). A very common requirement is 100 hours minimum, and most people come out of their PPL with around 60.
The minimum hours requirement is generally suited to the owner. The higher the restriction, the cheaper the insurance, so owners will generally get insurance with the highest minimum hours restriction that still allows them to fly their machines.