The inherent risk is that if China decides to test this doctrine and is willing to risk 'acceptable' casualties, then a limited war is possible.
I don't think the Chinese will ever test it.
They don't have the force to spare any "acceptable casualties."
Even small losses to their modern forces would send them back to pre-1996 in terms of military capability.
The Chinese are vastly outnumbered by US and its allies. And it's modern forces are small and struggling to keep up to date (e.g. most equipment entering Chinese service now is basically 1980s/early 1990s technology).
And by the time the 2030s have rolled over, the Chinese are still playing catch up – the US and allies are currently introducing next generation systems (aircraft, tanks, air defence, theatre missile defence).
By the time these systems reach Chinese frontline units, the US will have shifted to the next area.
The only risk is if US starts to wind down its military due to economic sustainability or if current issues with Russia and Middle East become more long term.
But the US has clearly urged China to follow international law and UNCLOS,
Ironic given the Chinese have generally followed international law over the last 70 years and the US generally doesn't.
even if it did not outright reject China's historical claims.
They have basically outright rejected China's claim on Senkakus and South China Sea Islands.
With Senkakus, the US has stated they fall under the jurisdiction of Treaty of Mutual Cooperation and Security between the United States and Japan.
This was confirmed by President Obama in April.
In essence that acknowledges Japanese control of islands and disregards claims by PRC and Taiwan.
The US has also supported Philippine claims by again asserting defence ties and providing military support for Phillippines to enforce claims (e.g. provision of ex-USCG cutters).
US is also offering Vietnam military equipment specifically for South China Sea area – e.g. -P-3 Orion maritime patrol aircraft.
It's clear the US does is biased towards countries opposed to China, even if it involves old enemies ala Vietnam.
It's also clear that the US expects China to backdown.
I've always said it: US prefered position on China and Russia is for them to be swallowed by the earth (but Arab terrorist sponsoring political donors are more than welcome to hang around).