Is Parking Legal When the Sign's Obscured?

Is Parking Legal When the Sign's Obscured?
Heavily stickered signs on the west side on South Anaheim Boulevard, between Santa Ana and Water Streets. I recognize Popeye, the Vikings mascot, and (an oddly blue) Hot Stuff (with a halo), but I have zero frame of reference for most of these stickers. And what are all of these crews? Dance crews? Mötley crews? Stickering crews? Are those a thing?

That really could explain the motivation!