As others have said, this would literally kill the faction. Increasing the time between ads also does not work because within the faction, minimum bulks are required for Weazel faction members to run (75 for each advertiser, 50 for each manager, and 25 for each media team every week). With there already being a time limit of 3 ads every 5 minutes. It's also the only way to actively communicate information across the entire city for information. IMO hiding this would further hurt already hurting Civ Roleplay in the city. In that same breath, you could say just have people post their items for sale on LifeInvader only, which would just kill the RP as a whole. As a crim my phone was off 99% of the time to avoid tracing.
My suggestion would be to change the location of the advertising interface, maybe above the GPS like the Powerball UI or when your car is being broken into. Keep the text chat purely for RP text. I feel like there used to be a communication system in the city that allowed for ads there so the script may be easier to implement since we likely will not get a full phone overhaul.