The risk of untreated bacterial meningitis is a mortality rate of between 80% and 100%.
In comparison, the risk of a spinal tap is very small.
If you take your child to an ER and decide that forgoing a diagnostic procedure with a known low morbidity rate is reason enough to expose your child to a 5% to 10% chance of death, you are pretty likely to see Child Protective Services and the Police move in and take the matter out of your hands.
So you support the course of action taken by the MD and CPS? Tell me what gives you the right to decide between risk of death from lumbar puncture or meningitis in place of the parents? The parents wanted to wait a reasonable time before authorizing more invasive and risky intervention.