Someone who holds to "OSAS" does not necessarily believe that salvation is a license to sin. Not only are you confusing correlation (questionable in itself) with causation, but you are painting a very large group of people with a very large brush.You're describing the experience of the "Just Man" who falls but rises again, which is not the same as the OSAS "Presumptuous Man" who thinks salvation is a License to Sin".
How about this: IF you ever come across someone who actually believes that salvation is a license to sin, then address their error. Until then, drop it, because you're so far off base, you're playing in the next county.