Pranksters have tried and failed to slip past number plate police the lewd, the rude and the crude.
Some are so offensive they can't be printed here, blocked by South Australian Transport Department officials who have deemed them unsuitable for a general audience on the road.
In total there were 129 plate applications blocked in the past financial year, most variations in spelling of some of the most offensive words in the English language.
Many are immediately recognisable as phonetic spellings of offensive language, such as FORKING, or PHARQ.
Others have been banned because of sensitivity to victims and their families, such as KIDNAPR or H1TRUN.
Drivers of classic cars manufactured in 1969 are out of luck if their plate references the sexual position, and some body parts are totally off limits.
Officially, the department says: "In South Australia, a personalised or custom plate is considered unsuitable if it contains inflammatory or defamatory references in any language which could be considered by a reasonable person to be inappropriate for public display."
"This includes words that refer to racial groups, have a sexual reference, a religious profanity, offensive text speak or refer to gang names."
South Australia's Transport and Infrastructure Minister Stephen Mullighan said personalised and custom number plates are an increasingly popular way for people to individualise their vehicles, and they also provide a source of revenue for the Government, raising about $7.8 million a year.
More than 4600 personalised and almost 4000 custom number plates sold last financial year. Two years ago there were less than 8000 combined.
There were also almost 20,000 renewals of custom number plates, up from 17,299 two years earlier.
"While these plates are becoming more and more popular, it's important to make sure that they meet community standards,'' Mr Mullighan said.
"Generally we will allow words which are openly used in the community and that rules out combinations that are obviously objectionable, or contain inflammatory or defamatory references.
"It's worth noting that this may not exclude combinations which some people might consider in poor taste, cheeky or attention seeking, depending on their own perception of what they may personally consider acceptable."
Custom plates cost $200 a year for up to six characters and $255 for seven characters.