Question: On Area 51 meta someone asked a question about promoting his proposal which I answered [here](https://area51.meta.stackexchange.com/a/28317).

Now on Stack Exchange since we don't like spam I don't like the idea of someone spamming something from Stack Exchange on some other platform, so I said in the most friendly way possible not to spam anyone in my answer. (*Small text at the bottom*)

But, should I have said this, is there anything wrong somehow with this simple reminder? It felt kind of rude in a way.

Answer: 
I don't think this simple reminder is rude, and it's not wrong.

It's always fine to remind people not to spam and to respect the users using the website. If you feel like it's rude to the user, you always have the right to remove it. 

I also don't think you have to put the reminder in since most users know it's unrespectful to spam on websites, but you still have the right to remind people not to spam in a friendly way.
Although I sometime see small text used within posts, I personally think it is undesirable to do so, because my first thought is always "I wonder what they want to try and hide in the fine print". If it is worth saying then I think it is worth making it easily readable.

I think we all know that spamming is highly unpopular, and so your fine print can go without saying. If people spam here downvotes and spam flags quickly discourage them, and I think it is up to other sites to perform their own spam control to the level that is desirable for them.