A Facebook post is making the rounds again that suggests that drivers should call 112 to verify whether or not an unmarked police vehicle is real. Don’t do it!

The fear of people masquerading as police officers in unmarked vehicles in order to stop and rob or assault unsuspecting drivers is a very real fear. There have been several news reports over the past year of events like this including one in which a female off-duty police officer was pulled over. However, the advice circulating in social media to call 112 to verify if the unmarked police vehicle is real or not is bogus and it’s causing problems for law enforcement.

The story circulating on Facebook supposedly tells the “true” story of a 19 year old woman who suspected the unmarked car that was trying to pull her over wasn’t real. She called 112 or, in similar stories #77, and was told by the dispatcher that the “cop” trying to pull her over wasn’t real. Shortly afterwards, the fake cop was surrounded by four real cops and the story had a happy ending.

The problem is that 112 is used as an emergency number in some countries and some, but not all, cell phones are programmed to automatically switch over to 911 when 112 is dialed in the US. When the story first popped up in Facebook several years ago, so many people tried calling 112 to see if it worked that 911 switchboards were flooded with non-emergency calls.

If you’re pulled over by an unmarked police car, law enforcement agencies do encourage drivers to call 911 to verify that it is, in fact, a real police officer that’s pulling you over. In a situation like that, don’t waste time calling 112 and waiting for it to shift over. Your cell phone may not be programmed to shift over to 911. If a real officer in an unmarked vehicle signals for you to pull over, he or she will also understand if you motion for them to follow you to a well lit, populated area before stopping.

People certainly shouldn’t call 112 just to see if it works because, if your cell phone is programmed to shift over to 911, you will have committed a crime by calling 911 for non-emergency purposes.

Read more: Dial 112 to Contact Police in Emergency?