Rolling black out is common around here but some do abuse it. I know someone that was written a reckless driving citation for getting too close to a cruiser that was running blacked out. The LE refused to admit he was running blacked out until the 3rd or 4th court date. Until he was finally convinced the driver was going to take it all the way to a trial he tried to stick it to the guy for his being careless. The LE was driving through an industrial park at shift change with his lights off and then went off on the driver for getting too close to his cruiser.
I don't see anything wrong with it if the LE has enough smarts to realize the good guys also can't see them and drive accordingly.