Its all too common.
The system is this way because there is a lack of standardisation across PhDs, no real definition of what is adequate supervision and no set "rights" of PhDers (unlike staff or undergrads). Its a recipe for exploitation, and insecurity.
More and more I can see the effect it has on my PhDers. Some are becoming a shell of the person they once were, half of them are recieving student counselling and I find frequently find Prozac boxes in the litter bin.