Guernsey Police says it is working on two serious investigations linked to the use of 'Facebook taxis'.
The term refers to lifts organised by local people through Facebook groups.
Users of the social media platform will usually post requests for pickups and then are messaged by drivers but concerns have been raised over safety.
"The majority of drivers offering Facebook taxis are also not licensed, so even if they are providing the lift with good intentions, if there was an accident, there would be no insurance cover," Guernsey Police said.
"We can never know what the intentions of a stranger are and getting into a stranger’s car, particularly after enjoying a night in town, can leave you vulnerable."
The force says it will be checking in with people who are getting lifts to make sure they know the driver as part of an initiative named 'Operation Wigan'.
It follows last September's damning 333-page independent report into Guernsey's taxi industry which highlighted the need for "radical change" as people turn to illegal lifts to fill gaps left by a sector that "fails to provide a decent service".
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