As I type, I'm watching the Australia New Zealand Test match and despite having a 265 run lead on New Zealand, Ricky Ponting started to put guys at deep point and and deep backward square in the 3rd over after a bright start by New Zealand (Jamie How hit Stuart Clark through backward square for four and next ball there was a man there). With the lead he has, would you not think he has runs to play with, so he could afford to give some runs away, espcially through the covers as you can get wickets caught in the slips or if you encourage him to bowl straight then bowled, caught behind and LBW comes into play? We saw it on day 2 as Daniel Vettori was going on the defensive quite early, as if to try and strangle the Australians (not that it worked) and hope they get out. In Nagpur, MS Dhoni went out and strangled the Australians and got 8/166 on day 3.
So my question is: If you do not get early wickets you go on the defensive to limit the runs conceded and hope they get out to a bad shot or (if your in the case of Ponting and the lead he has as my example) you be prepared to give away some runs for wickets? Or indeed is this a new trend amongst Test captains?