Mario Says Cops Can Show Restraint If They Want To, They Just Don't

Mario says police can exercise restraint when they want to, but most cops just don't ... a lesson he's already learned first hand.

The singer joined us Thursday on "TMZ Live" and recounted his recent run-in with police in Miami, when guns were drawn and an intense standoff was diffused only when an officer realized he was a celeb.

Mario says he was caught off guard when police stopped the car he was riding in and held him and the driver at gunpoint ... he says he was very lucky one cop recognized him because things could have turned ugly in a hurry.

The incident left Mario shaken, and also taught him a hard lesson ... he says cops can practice restraint whenever they want, especially when another cop steps in, but for some reason most police just let their instincts take over.

Mario's also got a new single out, "Rewrite It," and he tells us the inspiration behind it, and how it ties into protests against police brutality.