The question which doesn't seem to have been raised is why they were only 'tampering' with one of the two balls. Or is the point that the umpires had a suspicion, but nothing that could remotely constitute "proof", and therefore just changed one of the balls as a warning (they obviously couldn't have changed two of the balls for being 'out-of-shape' and covered it up).
The flip side of this of course is their suspicion could have been totally groundless, which explains England's complaint at the ball being changed.
A further suggestion somewhere between the two extremes might be this: there have been suggestions of umpires trying to clamp down on some practices designed to generate reverse swing - especially throwing the ball on the bounce (as pointed out in the cricinfo article above, this is difficult to enforce since one of the reasons for returning the ball on the bounce is that it arrives quicker. And frankly, why on earth should the practice be outlawed???)). Maybe the ball change was because they felt that its condition had been altered excessively - but not by 'scratching' (which frankly would be pretty obvious, as well as hard to cover up from the TV cameras), but simply by the range of other 'legitimate' practices that were going on. And if so, its no wonder that England were peed off by the decision, and many i think would conclude justifiably!
The flip side of this of course is their suspicion could have been totally groundless, which explains England's complaint at the ball being changed.
A further suggestion somewhere between the two extremes might be this: there have been suggestions of umpires trying to clamp down on some practices designed to generate reverse swing - especially throwing the ball on the bounce (as pointed out in the cricinfo article above, this is difficult to enforce since one of the reasons for returning the ball on the bounce is that it arrives quicker. And frankly, why on earth should the practice be outlawed???)). Maybe the ball change was because they felt that its condition had been altered excessively - but not by 'scratching' (which frankly would be pretty obvious, as well as hard to cover up from the TV cameras), but simply by the range of other 'legitimate' practices that were going on. And if so, its no wonder that England were peed off by the decision, and many i think would conclude justifiably!