'Cemeteries' are a unique hybrid of park and graveyard which were originally designed to be enjoyed by the general public. I regularly cruised through Rosehill Cemetery in Chicago on my daily rides and never experienced a problem with outraged visitors or anything remotely close to that.
Having said that, I try to avoid them on weekends as there seem to be a lot of burial ceremonies going on and more than just 'visiting the tombstone of a loved one' visitors.