I should say, "Use your head."
Last week there was an Reuters article about cyclists not using helmets. This was already discussed elsewhere so I'm not going to go into detail, but one part in particular caught my attention.
The risks of cycling without a helmet are even higher -- the group cited the Insurance Institute for Highway Safety as saying 92 percent of bicyclists killed in 2007 were not wearing helmets. Helmets reduce the risk of head injury by 85 percent.
Throwing numbers out like that can fool people into thinking that a vast majority of the 92 percent of killed cyclists would have lived had they been wearing a helmet. What they don't tell you is how many of those cyclists died of head injuries that a helmet would have protected them from. Now I'm not saying you shouldn't wear a helmet--you can ride safely with or without one--but don't let statements like this go without challenge.