It's legal and widely available, I believe one was even posted on the forum a while ago (correct me if I'm wrong?)
Many others use them, and I used to play with a few activated too, and nobody really said anything to me about how "unfair" it might have been. You might make a rule in your tournament that disallows the use of such scripts, although since some scripts display damage to just the player who has it activated then there's no real way of tracking who uses it or not, unless you ask them. Tbh it isn't that much of an advantage, on my old computer I used four scripts to tell me damage, bullets, nade damage, etc, everything, and I never bothered to reinstall them when I got my new PC. People who use them and think they're amazingly useful are just kidding themselves.
Many others use them, and I used to play with a few activated too, and nobody really said anything to me about how "unfair" it might have been. You might make a rule in your tournament that disallows the use of such scripts, although since some scripts display damage to just the player who has it activated then there's no real way of tracking who uses it or not, unless you ask them. Tbh it isn't that much of an advantage, on my old computer I used four scripts to tell me damage, bullets, nade damage, etc, everything, and I never bothered to reinstall them when I got my new PC. People who use them and think they're amazingly useful are just kidding themselves.