It's been discussed a few times at least to my knowledge. I don't think it's implausible but that can be disputed, depending on what and when the POD is of course.
IF we start after the assassination of the Arch Duke, then I think we need the British cabinet to decide its red line is Germany passing troops through Belgium and otherwise it would not intervene in support of France. It also has to communicate that clearly to France, Russia and Germany before mobilisation. In that case there's a chance that Germany mobilises only against Russia and that France may stay out too. which would get Russia to back down. A chance, not a certainty or even high probability.
However, any such action would mean the end of the Entente Cordiale, which means it's implausible. Also, if war breaks out anyway, the Liberal government would be vulnerable to defections that would bring the Conservatives back into power. And a Tory-Liberal Imperialist would likely take Britain in later.
No Entente Cordiale probably requires a POD pre-1900 and different actions by both Britain and Germany. Difficult to see whether France and Russia would still be prepared to risk war in July 1914 without the expectation of British backing, though Germany might still feel war then would be better than when Russia had industrialised more heavily and modernised its forces.