Umm... couple o' things...

Trics are not a defense against cold weather. As an annuals, the only " defense" against damaging cold that cannabis sp. possess is reproductive selection toward earlier flowering individuals. They adapt to local conditions, rather than fighting them.

Remember- the plant's only goal is to produce viable seed ( or, more precisely, viable reassortments of it's genome) - a sunscreen which happens to have , under some circumstances, psychoactive effects on some mammals is really incidental, as far as preventing damage to the seed chromosome. The only way in which " potency" is a reproductive advantage is that humans are more likely to husband the seed of more potent parents

Ain't no such thing as 30% THC (wet weight) in any strain, anywhere- pre-decarboxylated d9 acid, at room temperature, is gonna be a liquid. Given that we can expect 80% weight loss during the drying period, bud @ 30%(wet weight) THC would be either a gel or a slurry- I'm not sure which. Anybody got a Merck handy?

I know that breeders will claim very high %'s- All I can say is that they must be using some neat math.