How can we punish someone for something they didn't do?
If they missed they haven't killed a guard, therefore they have not rebelled and taunted which is allowed unless otherwise specified.
Not only that but it opens what is a clear cut into something where the warden, an often biased individual decides whether or not a user was trying to kill someone, rules that are open to interpretation should be avoided at all costs.
If you find this is an issue then declare lethal taunts or all taunts are KOS when you are the warden.