Just out of interest why is wearing a helmet a detrimental thing? Apart from the looks... Is there evidence to say you are more likely to get brain damage by hitting your head on the floor with a helmet on?
Some reasons why helmets are worn:
It is common sense, a "no brainer", a layer of protection between your head and the ground is obviously a good thing.
The counter argument:
Your skull is about 20 times harder than polystyrene.
A helmet makes your head much bigger so more likely to hit something.
A cycling helmet does not have a polished smooth surface with an outer membrane that would then allow it to slide along a road surface without snagging and possibly twisting your neck. [rotational injury], vents make this even more likely.
Despite better reporting of head injuries, there has been no reduction observed.
Neck injuries that have occurred after a cycling incident by those who wear a helmet are not recorded, also not recorded as far as I am aware are those cyclists who were not wearing a helmet in an accident and did not have a head injury.
The cause of brain injury is the acceleration and de-acceleration of the brain against the skull [excepting penetrating injuries - rare], a helmet does nothing to stop this.
Purely anecdotal, and in some measure from forums such as this, those who choose to wear a helmet appear to hit their heads more often.
Pro cyclists wear them so it must be the right thing to do.
CA:
The governing body of pro cycling, the UCI have a pretty abysmal track record when it comes to decision making, those who follow pro cycling will understand this.
Amateurs will blindly follow whatever the pro cyclists wear in order to look like them.
It will become law because the percentage of those wearing a helmet is growing.
CA
Difficult to comment on this as no firm evidence is available, certainly amongst those mamils new to cycling, but no evidence to show all cyclists are following this trend, perhaps the reverse in some areas of the UK. In other countries, particularly The Netherlands, Denmark and to a large extent Germany helmets are not worn [except by mamils, and then not all], even children who ride to school [not all on cycle paths] do not wear helmets.
Would I wear a helmet if it could be proven beyond reasonable doubt that it will make me safer? No, simply because I do not think cycling is a dangerous activity, to promote any other view is in itself dangerous. There are many cyclists who only wear a helmet because a non cyclist [usually a relative] have told them to do so.
I am probably unusual in that I believe helmets actually cause injuries, not the superficial type as in road rash etc but in neck injuries. There are also head injuries which would never even have occurred had a helmet not been worn.
Helmet sales are a billion pound industry so your local lbs is highly incentivised to sell you a helmet. Other third parties may have a vested interest in these sales which may or may not have a skewed view on helmet wearing.