There's a lot more to Martlew's bill - Protective Headgear for Young Cyclists - than meets the eye.
The MPs who have signed to date may not have read the fine print. They may have pledged their support because 'anything that saves children's lives has got be worth supporting'.
However, should the Bill be passed, Martlew's lid-law would soon be found to be unworkable in practice. Will the police really fine teachers for making sure children wear helmets?
Bike shop owners are also wondering how the lid law would impact on them. Steve Barnett of Cycling On in Longridge, Lancs, said:
"The bill as written seems to allow for spot fines to be placed on the last adult in charge of the bike before the child was found riding without a helmet. It means that I will have to ask for positive proof of age from anybody collects a bike for repair.
"If somebody under sixteen took a repaired bike from my shop and was later seen riding it without a helmet then I would be fined.
"Bike shops are child magnets. Suppose a child rides his/her bike to the shop and brings it in - they often do - and then rides off without a helmet, am I the last reponsible adult and could I be fined?"
According to Martlew's bill, here's who cops the fine if a child is found not wearing a helmet when cycling: "any person other than its owner who has custody of or is in possession of the cycle immediately before the child rides it, if that person is above the age of 15 years; where the child is employed, his employer and any other person to whose orders the child is subject in the course of his employment."
Parents may make their children don their helmets when leaving the house but - as the bill now stands - it's then up to other adults to make sure the helmets stay on. Fail in this task and - ker-ching - you're fined.
Adults this would effect includes teachers, newsagents who employ paper boys and girls, bike shop owners and staff, and many others.
And, should a child have a cycle accident and injure him or herself, adults who should have made sure the child was wearing a helmet, could be sued by parents for failing in this task.