New (to me) in game warning: "Don't shoot the civilian vehicles"

Playing Fallujah the other day (with Ray-Ray) as gunner in an LAV...I don't play in armor squads much but am wanting to branch out. Anyway, while in Therms, I noticed a nearby (Arches) and unoccupied Civie vehicle was glowing hot while another beside it was cold. I guess the latter was part of the environment and the previous usable by Insurgents? I got nervous about it potentially being a bomb car and/or a general threat to the team and proceeded to lay .50 fire into it. Then, the game posted a warning saying something to the effect of "You're job is not to shoot civie vehicals"...no, I can't relay the exact words because I ceased fire and the warning disappeared.

Q: Is shooting unoccupied civie vehicles some type of rules violation?

Hoping some of you guys who play armor a lot can shed some light?

Did admin warn you or the game? If it was admin then...idk. If it was the game then that is understandable. In most theaters of war one objective of the the Marines (or U.S. Armed Forces) is to not cause damage to civilians, civilian property, and civilian infrastructure. I think blowing up unoccupied cars is a similar penalty to shooting a civilian. If it Is not a bomb car and it Is not occupied by insurgents, blowing it up is causing damage to civilian property. So don't just shoot cars for the hell of it.

It is a in-game message that pops up in insurgency maps. Same as shooting civis and not arresting them.

I don't know if destroying the cars hampers the team's intel (which would make no sense...) but they do affect your personal score. Anyway it's not an admin warning

Its the same as shooting civi's. Its in the changelog.