I fully agree, this simple option is highly needed.

Actually, I came here to create the same topic, because the friendship request spam is getting more and more aggressive on Zodiark. I often get several per hour, mostly or always from the same RMTs (a few weeks ago, they went over to using their URL + 2 or 3 letters at the end as character names) and always from Ul'dah, Steps of Nald (since i have started to play this game in December, ALL friendship request spam comes from there).

An option to block these requests would be a big relief, since they are much more annoying than RMT /tells (if /tell sound is switched off). Also because the procedure to decline requests and blacklist the spammer is indeed unnecessarily long.