With blid not knowing how to handle his requests very clear i'll just lay out how a moderator should issue a request to someone whether it be flaming, spamming or whatever.
Post your initial message. And then
Make the Request known by making it stand out so
A) The person does not miss this as they are skipping through posts as it stands out
B) The person knows that are clearly being issued a request/warning
Get it? Got it? Good.
Brought to you by the human vessel of Lucifer, Sam Winchester from Supernatural.