I would question why you needed the disconnect for the garage at the house and the 4 wire feeder to the garage in the first place. Why not just have the disconnect at the garage fed with 3 wire USE and SE running top the disconnect in the house?
That looks like the "Maypole" setup we see a lot around here. If the meter was on a post there wouldn't be a question IMHO.I don't see hanging on the house changing that much if the SEC to the garage left immediately.
I do agree that in an emergency situation a fireman might assume that was the house disconnect. They don't usually stop and read signs if they think they know what they are doing. That is all the time
