I think it should be aloud if you whisper it and only people within a certain radius can hear you, like maybe one or two metres around you. Like when you get mugged in the face by someone coming out the same side of the barricade as you and they're ramping and you end up bleeding out of your teeth (true story). I reckon it's ok to whisper a little "Damn and blast you" as long as not many people hear it.