I've always been curious about "they don't allow it"? Really? I can't find this rule anywhere. Actually dripped some very GREEN anti-freeze at a national event a few years back. All they cared about was did I have the leak fixed. Compared to synthetic oil, cleaning up antifreeze is not a problem. With 75psi oil in several hoses, and 5-10 psi in the cooling system, I worry about oil before coolant.

It will make NO difference what you have cooling your motor if it leaks and gets under the tires.

RIP