I suspect you are confused or have bad information. A Cruz waiver is an agreement that a defendant may be sentenced to a greater term than the plea bargain if he doesn't show up for sentencing. I have never heard of a Cruise waiver.
Mr. Kaman is absolutely right and I have seen folks not show up and get years in prison more than they would have, had they shown up.
My standard disclaimer: I am not offering legal advice, assume I do not know the law in your state and that I am just making suggestions. Do NOT rely on anything I write and contact a lawyer in your area immediately for real legal advice.