As far as what is unprofessional, this depends entirely on the context. for example, if a cop wants to look inside of a car to see if there are drugs or something else illegal in it, they would obviously need to touch the back of the car for that. it does not matter that it might be “unprofessional” because it is necessary for them do their job. however, touching the side of somebody's car could absolutely be seen as unprofessional because nothing needs to happen at the side of someone's vehicle anyway – all interactions are supposed to occur with people besides cars! a cop can't stop somebody for no reason and search their car without probable cause or consent from an owner–so whenever they do stop somebody
why do police officers tap the back of a car?
the odds of a person being armed is proportional to the complexity and seriousness of a crime, with serious crimes having a higher likelihood of someone being armed. with that in mind, police officers tap the back because they need to be extra cautious when confronting people who have committed more serious offenses.
the best answer is no answer
can you tell a cop not to touch your car?
no.
you can ask the officer not to touch your car, but you are not within your rights to tell them they cannot. any possession of a vehicle is considered evidence and can be destroyed or damaged without penalty from an officer. for this reason, the police should always inspect the car for fingerprints or any other potential evidence that could lead to a conviction of a drug dealer, for example. if an individual is entirely unwilling to allow their belongings to be investigated by law enforcement officers in furtherance of public safety and national security, these individuals need only refuse cooperation with authorities and request a lawyer – after all, our freedoms come with a price tag- personal responsibility!
