The unfair-play has been introduced. Is this appropriate for use on Sports SE?
The concept of "unfair play" is quite subjective to the community as a whole.
However, since tags age away automagically if they are not adopted and used on more than a question, I'm not too worried about it. As it is it's not currently on any questions so it will die shortly.
I'm inclined to say that it's more positive cousin fair-play is more appropriate, but that's just me.