It's a disgrace it's not acted on by referees, it's even less ambiguous than kicking the ball away, I can truthfully say I've been booked for kicking the ball away when I'd no idea the whistle had gone in a noisy game, that defence is gone if you pick it up.
Also leathering the ball into row Z when it's clearly gone out for a throw in, corner or goal kick, although that's harder to police.
I’ve received yellows for kicking the ball away, as well. On a few occasions I knew exactly what I was doing. I would not have even thought of doing it had I known I was going to be summarily sent off, though, which is why I advocate for them being red card offences.
Clearing the ball that is already out should probably be a yellow, though, as you said, it is difficult to ejudicate.
Another thing that frustrates me—even when our players do it—is standing over or in front of a dead ball after your team has given away the foul, in order to delay taking of the free kick. It completely negates any advantage given to the team wronged and even, in most cases, means the foul was entirely the advantage of the team committing it (as it stops a promising action/movement and allows the offending team to get players back in position to defend).
I have always thought that the rules should be changed that such an action should be an immediate yellow and free kicks occurring in the defensive and middle thirds of the pitch (dotted lines could be drawn on the pitch to demarcate the zones) should be allowed to be taken immediately within a 10 yard radius of the place of the foul, as having to take the kick at the “exact” position of the foul, when the ball often rolls off on its own after the foul, is also disadvantgeous to the wronged team.
I am sure some would argue this would impact our play (as we are apparently the masters of the dark arts), but I would assert it would more heavily impact less skilled, more physical teams, benefiting the higher quality sides and leading to more innovative tactics to stop them than just taking turns kicking lumps out of the best players on the pitch.
Edit: reading that back, I now realise how frustrated I am about the current laws of the game, haha.