> And remember than your phones can be turned into servers
I wouldn't turn a cell phone into a server without also disabling the wireless chipsets somehow. Knowing that some unknown number of people working for your phone manufacturer, your wireless carrier, and Google or Apple have privileged access, including the the ability to remote into your phone at any time and add/delete/modify files and install software, without any notice or even indication to you that something has been done isn't the kind of security/privacy I'd want on a server.
It happens all the time on the OS/carrier/manufacturer side. I've personally seen settings reverted, software installed without notice, etc. It's a lot harder to say what any random cell tower in range is able to do but the chipsets are closed source and have their own OS.
Manufacturers and carriers have had it in their terms of service that they can do it.
Here's what tmobile had in their ToS:
We may remotely change software, systems, applications, features or programming on your Device without notice. These changes will modify your Device and may affect or erase data you have stored on your Device, the way you have programmed your Device, or the way you use your Device. You will not be able to use your Device during the installation of the changes, even for emergencies.
On a 5+ year old device that no longer has a data plan? T-Mobile's TOS doesn't apply during that time.
Plus, you know this is about software updates, right? It's generic but that's what it's about. Yes, upgrading means removing files at times as things get refactored or become obsolete, but they're not going to touch your main data, not that software isn't shitty and accidents happen.
I wouldn't turn a cell phone into a server without also disabling the wireless chipsets somehow. Knowing that some unknown number of people working for your phone manufacturer, your wireless carrier, and Google or Apple have privileged access, including the the ability to remote into your phone at any time and add/delete/modify files and install software, without any notice or even indication to you that something has been done isn't the kind of security/privacy I'd want on a server.