It's up to the child's parents to decide what is appropriate for their child's needs. Tough if it makes other people feel uncomfortable, the child is more important. I suspect the mum is fed up with people interfering with useful advice on parenting skills, she's probably relieved to have found out what is making her child be like he is at times and wants everyone to know it so they stop judging her and her son. The lanyard is designed to stop the judgement calls not for someone to query whether it should be used.
I am disabled, use a wheelchair but can walk a little bit, I have a blue badge and have had one for about 20 years. I still notice people will stand near car when we park in disabled bays to check out whether or not someone in the car should be using a blue badge. I don't need to be made to feel uncomfortable by people checking on me, they should mind their own business. I suspect the mum of that child feels the same way.
Ah dear - why does getting older equate to diminished brain power?


