The Signal Jammer
The Signal Jammer is a blanket correspondence ward enveloping the Bay area as well as all major metropolitan areas thanks to a ward that a Virtual Adept set off in 2000. This ward infects other phones when receiving a text or phone call, and the amount of affected devices has, by now, skyrocketed to a staggering number throughout the world. It creates an unpredictable landscape of fluctuating but ever-present Correspondence wards that provide protection against telenuking but also provides unwelcome barriers to scrying.
When a mage wishes to scry into an area within the bay area, the storyteller factors in any deliberate wards other players have put into the target area and adds on top of it the successes of 5d10 vs 6. If this area has poor cell coverage, add 3d10 vs 6. If the area has no reasonable cell coverage, do not add this ward.