David Coulthard believes Michael Schumacher's defensive display against Lewis Hamilton at the Italian GP was a classic example of the German knowing how far to push the rules.
The McLaren camp have voiced their unhappiness with Schumacher's defence at Monza after he appeared to make a double move to defend his line against Hamilton on Sunday.
Jenson Button claimed Schumacher's driving wasn't "all that bright" while team principal Martin Whitmarsh described it as "pretty harsh".
"I am not the least impartial but the fact is, I think he was warned twice by the stewards during the event so they presumably saw it was a bit tough," Whitmarsh added. "I think the one where he had Lewis on the grass was a scary as hell."
BBC F1 commentator Coulthard feels although Schumacher's defence was "robust", he didn't overstep the mark.
'My view, based on the images we saw, was that his behaviour was right on the limit but arguably not over it,' Coulthard wrote in his Telegraph Sport column.
'It was classic Michael; he knew exactly what he was doing and took it as far as he could.
'I mean, it's not often you hear a team principal repeatedly reminding his driver to leave another driver enough room, as Ross Brawn did following conversations with race control (just to be clear, as I know this was a talking point afterwards, such conversations are standard procedure; this was not special treatment for Michael).
'Others feel differently, of course. Jenson (who had a prime view and who knows better than I what is agreed upon in the drivers' briefings these days) felt Michael had consistently made more than one change of direction. Perhaps he is right.
'I'm not sure we will ever know for sure, and this is my problem with Article 20.2. It is not an exact science. It says that "one defensive change of direction" is allowed but does not specify how large that change of direction might be.
'And if you then drift back slightly towards your original line, how much is too much?'
One cause of concern for Coulthard though is the lack of consistency when dishing out penalties for double movement when defending your position as Hamilton was slapped with a 20-second post-race penalty at the Malaysing Grand Prix for 'weaving'.
'The problem is every race has a different set of stewards and a different drivers' representative, so the interpretation of the rules is likely to be different too. I can well understand Lewis' frustration in Italy, although he bit his tongue admirably,' he wrote.
'The only way to be consistent would be to measure Michael's exact level of deviation from the racing line on Sunday compared with Lewis's in Malaysia.
'In fact, that is what I believe they should look at doing. Just as football should get in the 21st century and embrace goal line-technology, so F1 - supposedly the pinnacle of technology - should use every tool at its disposal in an effort to be consistent.'