Buying coins from third party and sharing log in

That's a lot of caps, but to your point, no this is not allowed and never has been. coin buying, transferring, trading and even promoting is against the rules. However the way these things are punished seem to be very random. There are several "high profile" YouTubers that promote coin selling that never seem to get banned or punished, I have reported several of them along with their username and team name but their still there.