How would you? If the concussion symptoms are delayed then they wouldn't be taken off. I would assume the protocol would be to have a look at them and talk to them and if there are any concerns, perform the tests. If they were lucid and displaying no signs of concussion whatsoever, then further testing wouldn't be required. That is what Port seem to be claiming here and to eb frank, looking at the incident they clearly have zero to worry about on the Butters front (he is up within 10 seconds and is more interested in the giant hole in his face). I assume the AFL will ask the question about Jonas.
Mate, sleep on it, you are embarrassing yourself