Risk Management in Theory
Risk management is a concept with a very sound foundation.  That is, the cost of responding to unanticipated problems is always much larger than the cost of risk responses planned well in advance.  Further, if we keep the scale and cost of our risk management in proportion to the scale of the project and the risks we are avoiding; risk management always more than pays for itself.
Risk Management in Practice
Project managers routinely feel a great deal of pressure to start work on a project quickly since many executives think planning and risk management are simply bureaucratic paper shuffling processes with no real-world pay off. There is some truth to that assumption, particularly in bureaucratic organizations where any activity like risk management is an opportunity for more papers, more procedures and more endless meetings.  In addition, there is the fantasy that good project managers are good firefighters and so spending time and money on risk management is wasted.  When bad risks flare up; we just fight the fires.
Risk Management "Best Practices"In the Real World
Savvy project managers make a case for limited risk management using examples from previous projects of delays and cost overruns that were avoided because some risk management was done.  Wise executives respond well to those examples, particularly if the data is quantified from a previous project. Even the most skeptical sponsor will usually listen to arguments about the specific damage that can be done to the project completion date and budget by one or two specific risks.  A slow gradual education approach with executives works best.