Probation and orientation are two completely different concepts.
Probation means they can fire you at any time.
Orientation is when they are actively teaching you how to be a nurse at that facility. It usually involves double staffing (ie, you and your preceptor). Our orientation with a preceptor typically lasts 6-8 weeks, with another two weeks tacked on. On those last two weeks, you take all your own patients and do not have an assigned preceptor, but you do not count in staffing either. Therefore, everyone's load is slightly lighter, with the idea being we will all be able to assist you if you need additional help during this time.
I personally appreciate that we have a probation period. We have had a few instances where it has been obvious a nurse will not work out on our floor. I would prefer to be rid of them easily and not waste our time, rather than have them on the unit for a year while we build a case for firing them. We've gone that route, too, and honestly, it makes it miserable to work when you know you are working with someone who isn't safe AND you need to document and submit to your director all unsafe behaviors you witness AND you need to pick up her pieces AND (for us charge nurses) you hold responsibility for her actions.
During the probationary period, we've fired three people out of the last 15 we have hired. I worked with all of the nurses, and after a few weeks it was painfully obvious that they would NEVER be up to speed. One appeared to suffer from some extreme anxiety, wouldn't make eye contact with us, would disappear for long periods of time, and would speak so softly none of us could understand him. One had anger management problems, and actually left the facility while on break (did not inform anyone she was leaving), so that she could drive around and blow off steam rather than "punch someone's lights out" as she put it. The third could not figure out how to use our computer system. She COULD. NOT. FIGURE. IT. OUT. After three beginner classes and 4 weeks of hell, we kissed her good bye and wished her well.
If we would have not had a probationary period for these three, and would have had to spend months documenting issues in order to have enough incidents to fire them, it would have been hell for all of us, and dangerous for our pts.