It really was probably nothing. you could have pulled over and they would have talked to ya. Unless they had some kind of patch on there backs you gotta watch those guys some of them are dangerous. A lot of Bandidos here, so if the patch is red and gold leave them alone, easy enough.
Most really don't care unless they are newbies being led by a control freak, then they may over react.
I usually just pass when I get a chance.