Some don't like to wear fill brimmed hats, for style reasons.
They'd probably change their minds if they met Don Jamieson, a man whose lifetime spent outdoors has left him riddled with skin cancers.
"We're just trying to keep them under control," said skin cancer patient Don Jamieson.
He used to wear a cap, and it didn't help.
He's had more than forty operations and counting.
"You'd walk into a shopping centre and you'd hear kids say look at that poor man," said Jaimeson.
This plastic surgeon has seen too many patients like Don and says extreme measures are needed.
"Hats such as baseball caps, the baggy greens, certainly the lifesaver caps, they should all be banned," said plastic surgeon Ian McDougall.
He says the slip, slop, slap message has failed, "Patients come in and they say if only I knew, I'm afraid they did know but they didn't know well enough."
"Despite the criticism, Cancer Council Queensland is standing by the slip, slop slap campaign, arguing that research proves its working," said Cassie O'Brian of Cancer Council Queensland.
"We do know that melanoma rates have reduced and definitely people are more aware," said O'Brian.
He says this is the strongest message yet, "You try and just make people do the right thing or they end up like me and you don't want that no."
Dr. McDougall says the problem with the baseball hat is that it doesn't sufficiently cover the ears, cheeks and neck areas.
He suggests people wear a broad brimmed hat that covers those areas.