Balk or baulk: The word can be spelled either way; however, "balk" is more common in America.

When the purpose of the probationary period is to reduce salary for a certain amount of time, I also find it unacceptable. If, however, it is there to determine suitability, I have no problem with that. In addition, a probationary period can work to the advantage of the employee; if he/she finds that the job is not what they anticipated, they can then opt out and move on without consequence or complication.

I suppose that some FTs consider it as just one more annoyance, especially since it can be argued that those who make the determination of suitability are rarely qualified to do so. Fair enough, but I think what they're looking for in most cases is not one's skill as a teacher; that is, they are more concerned with conduct that may or not be appropriate in the particular classroom environment in which they are placed. For example, I can't imagine that I would be suitably placed as a teacher of young children. I'm not all that patient with children. Nevertheless, I may be interested in giving it a try because of the lure of a higher salary or perhaps the desire to work in a certain city - or whatever. In that situation, I think it quite fair that we, the school and I, are both protected by such a clause.