People will try to make a big deal out of this just because it's child porn but it's actually very understandable. Good call.
The law itself is understandable in the sense that it protects people who are unaware that what they are viewing contains underage people in it. The problem is that yes it does open the door for anyone to go out and "accidentally" look at it now and as long as it is not downloaded or saved then it is fair play.
So yes it is reasonable for honest mistakes but in no way is a great thing either.