High turn out indeed BUT of Russians, who are not Crimeans or?.

The most native Crimeans are Tatars and I would be very surprised if of those as much as 1 percent voted with the Russians.

Next are the Ukrainians of Crimea, who are most unlikely to be voting with the Russians.

The above two groups make up about 40% of the population there with immigrant Russians making remaining 60%.

So either the native peoples did not vote at all OR the voting was rigged.

I am of the opinion that it was the latter.