The safety factor on lifting straps is impressive, and when they do break it's a lot safer than having a chain or cable let go. I've seen chain links almost completely straighten and fly over 100 metres, and that was just with an old 935 Versatile pulling trees, God only knows what two D11's would do to a chain :

I was a recovery specialist and a mechanic in the United States army, I drove a Hemet wrecker... What you guys are doing here is very intelligent being able to break test your gear like this. We do a lot of farming here in Arkansas with some friends, it would be really cool to get down to an Australian farm and see how you guys do it too. Mainly corn soybeans rice and cotton here.

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That was very interesting and jolly good fun! Just looking at them, you'd never think they'd pull the amount of weight they do especially when they're so light.

In slow video playback mode, it can be seen that the belts were broken at the point of contact with the metal canine. That is, the straps simply cut themselves on the harder material of the canine. If you make a semicircular spacer from wood, it is possible that three belts would withstand the traction force. In any case, it can be seen that the straps are very strong.