I've never sprayed a bear with either peper spray or a CN/CS weapon. But I have spayed more than just a couple of people with both CN and CS tear gas. In fact, in order to allowed to carry or use them, I was sprayed with both.
That and I've seen both CN and CS used by several others on people. Those same people tell me pepper spray is alot "nicer" and not nearly as effective on people. It was adopted by law enforcement because tear gas was very unpopular, or, in other words, pepper spray is more politically correct.
Very emotional people, or those under the influence of some drug/alcohol do not "think/reason their way through being sprayed." If you were ever sprayed with either you'd know what I'm refering to. With CS gas, the biggest problem is straying on your feet and not vomiting.
Bears, to me at least, are far tougher/more emotional, etc. than people. Since I've seen and experienced such a poor record for CN/CS teat gas on agitated people, I have no desire to gamble with my safety by using it on a bear. E