Yellow cards in cricket

What is the world coming to?

Mark Taylor suggests yellow cards for sledgers.

In cricket the umpire is not running with the ball and hence he is always away from the scene of the crime. So how is he going to know whether anything offensive is being said or not.

Also imagine Bucknor summoning Symonds to come to him by blowing a whistle, then make Symonds turn his back to each and every scoreboard in the ground and flourish his yellow card.

Ridiculous isn’t it?