Yes, a error collector who would NEED such a coin would still be rarer than the coin, but you would now have the additional problem that some collectors who would want a No S dime would back off because they wouldn't want a double struck one. So now the overall demand would decrease and cause the value to go down, not up. This is the problem with Keys that have errors. They tend to be white elephants. The error drives off collectors who would want the Key but don't want it with an error, but it doesn't attract error collectors because they can find the same error (which is what they are interested in) on common coins at a much lower cost. So unless they are putting together a date and mint set all with an error, or the same error type, they have no interest. So rare date/keys with errors are often worth LESS than the same coins without the error.