The Twitterati were out in force within minutes of Sam Warburton, the Welsh captain, being sent off for a "dangerous tip tackle" by referee Alain Rolland during Saturday's World Cup semi-final defeat to France in Auckland.

The Scottish scrum-half, Rory Lawson, responded to the decision: “Yellow card, no-one says another word. Sam wrongly sent off.” And his compatriot, the former Test lock, Doddie Weir, was even more scathing in his judgment. “Really gutted for Wales – it was never a red card.”

Well, from a neutral perspective, those who denounced Rolland for not only spoiling the contest, but acting largely on impulse without consulting his touch judge, should study the rule book before lashing out in condemnation. Yes, it was easy to feel sympathy with Warburton, whose previous behaviour at the tournament had been exemplary and who could hardly be accused of launching a premeditated assault on the French winger, Vincent Clerc. Yet, once the dust had settled, the International Rugby Board was perfectly clear in justifying its reaction, even while the likes of Francois Pienaar and Lawrence Dallaglio were foaming at the mouth.

“The IRB memorandum, issued on 8 June, 2009, stated that such tackles must be dealt with severely by referees and those involved in the off-field disciplinary process.” Thus, although the judicial officer, Christopher Quinlan (of England), found “that there were no aggravating features”, Warburton was sunk from the instant he collided into his rival and hoisted him off the ground. Even Robert Jones, the former Welsh skipper, conceded that point, despite being among the vast congregation of heart-broken union aficionados in the valleys yesterday. “As disappointing as it might be for me as a Welshman, the Sam Warburton decision was the right one,” he said. “Initially, it looked fine, like a well-made tackle. But in slow motion, you can see that he has lifted Clerc and dropped him.

“If you go by the letter of the law, that is a red card, but I think the IRB have to look at that law, and give the referee the opportunity to base his decision on the way the game is going and the players involved. It is all about the feel of the game and there has been a lot of inconsistency with the officiating at the World Cup.”

Warburton has been banned for three weeks, and will now miss his country’s third-place tussle with Australia. The 22-year-old back-row forward rightly enjoys a lofty reputation as one of the game’s straight arrows. There is also a massive difference between his transgression and the petulant manner in which Wayne Rooney kicked out at an opponent during the recent European Championship qualifying match in Montenegro. But, Warburton’s offence was clearly dangerous and the IRB, which is striving to preach to the unconverted and spread rugby’s appeal beyond its traditional heartlands, recognises it has to tread a fine dividing line between maintaining the sport’s ferocity and convincing concerned parents that they should have no qualms about their children taking up the sport.

In this respect, one doesn’t envy them or people such as Rolland, not on the basis of the blizzard of opprobrium which was heaped on the Irishman’s shoulders. If he had missed the tackle, or adjudged that it only warranted a spell in the sin bin, one suspects that Wales, who had been a revelation in the competition, would have defeated Les Bleus, and booked their passage into next Sunday’s final against New Zealand. So too, Warburton, whose leadership of a youthful squad has been immense, would have been punished – and would probably have run the risk of being cited – without him being left to feel he had let down his whole nation. From that perspective, and particularly considering that Clerc was unhurt in the collision, Rolland’s handling of the incident was insensitive. Despite the subsequent heroics of the 14 proud Welshmen, who not only extinguished their opponents’ attacking threat but almost achieved a remarkable victory, there is little doubt the match turned on one sliver of overzealous physicality.

Perhaps, though, it also demonstrated how swiftly fortunes can change in sport. Prior to Saturday, the Welsh party had been so free of controversy, on or off the pitch, that Warren Gatland, their coach, was forced to deny his charges were living like monks. And Warburton was generally portrayed as the linchpin of this happy group; a blithe lad with a refreshingly good-natured approach to his craft and a fitting ambassador for his nation.

Briefly, at least, his halo has slipped a fraction. But it is rugby which may have greater dilemmas in the future as the tackles get bigger and the injury tolls mount.