Sony has started a new PSN username change service but this also comes with a useful feature that stops them from banning any PSN username that goes against the terms of service.
In the past, when users reported names that violated the terms of service for PSN, Sony used to ban them in some cases when the username was offensive. They will now replace their name with a temporary PSN username that can be changed by the user.
In an updated section on the official support website for PSN name change, Sony has mentioned this new rule regarding usernames that violate the terms of service for PSN. This also applies to someone who changes their username to something offensive and if reported, Sony will change their ID to a temporary username.
Why has my online ID changed to TEMP?
If you find that your online ID is now ‘Tempxxx’, this change was caused by a report from another player and an investigation by moderation staff, with a finding that your online ID has breached the PSN Terms of Service.
There are some examples of Sony banning users in the past based on their name. If your name was offensive or was made such that it is against the terms of service given by Sony, you were at risk of getting banned and thus losing all your online purchases or progress made on your profile.
There is less chance now of this happening since PSN Online ID can be changed now. There are still some risks associated with PSN Online ID change so make sure to read through all issues carefully.
Source (PSN Support)