If you're filming it aesthetically looks better to shovel them...... and if you don't shovel them it's not too urban in my book. An urban rail where the stairs are 100% covered is no different than a park rail without skirting. Shovel yo stairs.
If your claiming it as urban, ie if your filming or photographing, or bragging to friends about doing it, stairs must be shoveled off. If you just don't have the ridiculous amount of money needed for a pass to go shredding at your local hill, and you and your buddies just want to ride, then no.
Merse you sexy potatoe you better be doing some thing fucking crazy up there, see yea soon br-ah