Vandalism of cars parked in a street near Luton Airport was not investigated as no crime has been reported, police said.
Two holidaymakers' cars had been daubed with messages complaining about people not paying for airport parking.
A windscreen and windows had also been smashed.
Bedfordshire Police said that in order for the force to investigate it was "vital" that any crime was reported to them.
On Tuesday, Luton Borough Council removed a vandalised vehicle from Holly Bush Road, which had been left there for some weeks.
The council has the power to move vehicles if it deems the car to be abandoned or that it is believed leaving it there could lead to further criminality.
A consultation has also begun between local residents and the council, and a number of parking controls have been proposed.
A police spokesperson said: "We understand that damage to personal property is extremely frustrating for victims, and we take reports of criminal damage seriously.
"PCSOs have been deployed and will continue to carry out enquiries and reassurance patrols, as well as encouraging anyone who has information about crime in the area to come forward.
"This behaviour is not acceptable and should in no circumstances be a way to deal with community issues.
"In order for us to investigate, it's vital that anyone who has been a victim of crime, or who has information about issues in the area, to report it to us via 101 so we can take appropriate action."
Luton Airport said it would advise park on site or with a "reputable" off-site operator and that "like many other airports, our parking prices are variable and based on demand and availability".