This is ultimately up to the person who is paying *for* the advertising.
As I mentioned previously, if you make a post on Monday, start wearing a signature advertisement on Wednesday, on Thursday someone might read that post.
If this is something the person paying for the advertising is okay with there is no issue here. It is not your place to tell others how to conduct business.
Very well said, if the company is fine with this, it shouldn't be an issue, especially if he's the only user in the bounty. Maybe we should inform the devs?