To put it simply, No Sugar Alcohol's will not through you out of ketosis. The only thing that will knock you out of ketosis is if you take in too many carbs. And that level is different from person to person.
Unfortunately there is a lot of opinions, caused by fear and paranoia that gets passed around these boards as fact. Sometimes you just have to do a little research to separate fact from hype. Sugar Alcohol's are a perfect example.
Sorry Paradox but Sugar Alcohol's are not like regular alcohol at all. Sugar Alcohols are not burned by the body at all. It would be better to think of them as you do fiber. They have virtually no effect on blood sugar. They are simply passed out the body as waste. All though a lot of people worry about them and think that they my act like regular sugar they do not. Think about it logically. They are used in candy made for diabetic people. If there was even 1 % of the population that they acted like regular sugar in they could not sell them as diabetic candy.
I have read a ton of scientific data on Sugar Alcohol's and they all say the same thing. No effect on blood sugar.
I really think peoples fear of Sugar Alcohol's come from the old saying that if is sounds too good to be true.. it is. But there is that trade off, great taste vs laxative effect.