Currently the docs say (and the code agrees):

To run the vet tool with specific options, run 'go tool vet'.

This means that the careful argument construction that the go tool does, which takes into effect things like cgo, cannot be applied easily if one wants a special vet flag.

I propose to fix go vet to be more like go test, passing vet's own flags through. This will require a little code copying but shouldn't be too hard.