[Q] HTC - What exactly does S-ON restrict? topic

So, I have often received mixed answers to this and wish to put this to bed once and for all. I know that Motorola specifically restricts writing to /system (right?). But what about HTC's S-ON?

What partitions does S-ON protect? People have been telling me that S-ON also protects the /system partition but HTC's FAQ says otherwise. Here's a portion of their FAQ that talks about S-ON:

Quote:

Your device is shipped with Security on (S-ON) to protect your system software configuration (such as the bootloader, radio, boot, recovery, system and others). After you have unlocked the bootloader, however, you will have lifted the restrictions on boot, recovery and system. This means you can customize boot, recovery and system images on your phone as you desire. You can easily see that you have successfully unlocked the bootloader by looking at the top of the screen when entering the bootloader screen. Security is left on to protect things like the radio, and SIM lock.

They also say that:

Quote:

There are those who will insist on disabling S-ON purely to have full access regardless of security implications or to primarily promote specific tools and installation techniques that have taken the more convenient route of assuming all security is off. If a command line tool is deemed as inconvenient, developers can easily develop alternatives that would allow others to install their custom roms without having to alter their device’s Security-ON status.

So, then why do apps like Xposed Framework and others require me to be S-OFF to use them? Do they need to make serious changes to my radio and SIM lock? Going by what HTC says, S-ON shouldn't be a problem to me if my device is factory unlocked, should it?

Request someone to shed some light on this.