The L-Tag is a strategical weapon, very usefull in a team, in Crash Site games, for support. Good in long ranges and closed spaces, hard to kill someone with it in open spaces and at close range.
JAW or a Frag grenade... what's the difference; you will be killed anyway. And I think the Frag is more powerfull; it has a larger kill range.
There are many people who try to kick L-Tag players. Cut it. If server permits it, let it be.
And remember: players who use L-Tag, they just want to finish the assesment and get the dog tag for this weapon. So, let them play. I don't think there is a player so attached to this weapon, that is playing all the time with L-Tag.