Around a fifth (19%) of motorists have taken penalty points for another driver, a survey suggests.
Men are almost three times more likely than women to take the blame for another driver's offence, according to research commissioned by Co-op Insurance.
More than one in four (28%) men have accepted points for another motorist, compared with just one in 10 women.
Almost half (49%) of people who have illegally taken points have done so for their partner.
The most common reason for taking points for someone else is a belief that their car insurance is so cheap there would be no financial impact.
This is followed by helping the other person avoid a driving ban (23%) and financial gain (18%), with average payments worth £220.
Anyone caught can be prosecuted for perverting the course of justice, which carries a maximum sentence of life imprisonment.
In March 2013 former cabinet minister Chris Huhne and his ex-wife Vicky Pryce were jailed for eight months after she agreed to take his speeding points to avoid him losing his licence in 2003.
Drivers can be disqualified if they get 12 points within a three-year period. New drivers can also have their licence revoked if they receive six points within two years of passing the test.
Head of motor insurance at Co-op, Nick Ansley, said: "It's surprising and quite concerning that a fifth of motorists have taken penalty points for someone else.
"Penalty points are in place to deter people from committing motoring offences and to ensure safer driving for all on the roads.
"We want to ensure people are safe on the roads and whilst some drivers may think they're helping out another, by swapping penalty points, they're putting themselves and others at risk."
Some 2,000 UK adults were polled for the research.
Steve Gooding, director of the RAC Foundation, said: "As money-making schemes go this is one of the most flawed.
"Being paid a few hundred pounds to take the blame for someone else might seem harmless enough, but if you're caught then you could be found guilty of perverting the course of justice, the cost of which can be a big fine and even a prison sentence, not to mention a hefty hike in insurance premiums.
"Front-facing cameras also mean that often there is clear evidence of who was actually driving."