Suppose your friend is banned for few days and unable to make any post. But he needs to make an announcement which is urgent/necessary. So if he asked you for making a post on behalf of him. And you make the post.
So, In this case is there any problem can happen with your account? Is there any rules about this case? Just want to be clear about this. Thanks
If your friend is banned, he has the right to create a new account only to post in meta regarding his case.
If you are going to post an annoucnent that the guy is banned and if anyone wants to contact him to do it outside the forum, should be OK, at least for me.
If you want to take over a proejct, this should be fine too.
Normally those who post "of behalf of " somebody most offen turn to be alt accounts.