You are not a criminal. You endorse taxation, smile at police officers and keep your beard neatly trimmed. You read the world news section as you patiently wait for your morning espresso. You play it straighter than a gay 18 year old home for Christmas.
But sometimes a citizen *has* to ride on the sidewalk. A bike-lane went all Houdini on you. It's safer than salmoning. It's faster. Whatever.
So you take a little walk on the wildside.
You might catch your handlebar in the apron of a waiter delivering chicken soup to pavement diners, and end up being punched by a hungry mob while wallowing in broth.
You might have a little tete-a-tete with a car exiting a driveway.
You will certainly meet the quiet assassins: cross streets. The more insignificant the street, the more likely its gutters are precipices. Unless your frame is made of composites taken from a stoner's beanbag, you're gonna feel that jolt all the way up your spine.
BONUS TIP: Worse than cross streets is cross pedestrians. Noone knows when the foot-borne tribes got up to scratch with the law, but many are aware bicycles are vehicles under the law. They will recite statutes, lecture in shrill voices, grasp at your clothing. Nod sagely but don't dismount. You're not a criminal, remember?