Which Law? There are two: 10.4(e), which is clearly written for the general case, and 10.4(i), which is clearly written to protect a player jumping to catch the ball (including "in a lineout", which disposes of the "from a kick" claim")?
I would have though it was obvious that we were talking about 10.4(e) since we mentioned catching a kicked ball.
AFAIK, you can't kick the ball into a lineout (and no one has questioned the legality of hurdling the line-out )
The 1996 Laws did actually state the reference to fielding a kick
[LAWS]LAW 26. FOUL PLAY
Foul Play is any action by a player which is contrary to the letter and spirit of
the Game and includes obstruction, unfair play, misconduct, dangerous play,
unsporting behaviour, retaliation and repeated infringements.
<snipped>
(3) Misconduct, Dangerous Play
<snipped>
Notes:-
(iii) "Playing the man without the ball" and all forms of dangerous tackling
including early, late and stiff arm "tackling" or tackling or attempting to tackle a
player around the neck or head or above the line of the shoulders must be
punished severely. Players who willfully resort to this type of foul play must be
ordered off the field. Advantage should be played, but a penalty try must be
awarded if the dangerous tackle prevents a probable try.
(iv) It is for the referee to decide what constitutes a dangerous tackle, having
regard to the circumstances, e.g. the apparent intentions of the tackler, or the
nature of the tackle, or the defenseless position of the player being tackled or
knocked over, which may be the cause of serious injury.
(v)The following actions constitute dangerous play:-
(a) If a player charges or knocks down an opponent carrying the ball
without any attempt to grasp him (as in a tackle);
(b) If a player taps or pulls the foot or feet of another player who is
jumping in a line-out;
(c) If a player attempts to tackle a player who,
when fielding a kick in open
play, is off the ground jumping for the ball.[/LAWS]
That last bit, Note (v)(c) was the one I referred to when I said that the intent of the introduction of the "tackle in the air" Law was to protect that player, and that player alone.
I cannot recall if both the line-out and open play provisions came in in the same year (I think they did, and I think it was around 1993. I'm sure OB will know.