Additional moderators will help at least to remove such spam quickly. For example, in more than half of cases of spam messages like this I would be able to remove them very quickly (in fact, as soon as I get them into my inbox) if I have enough rights to do so... But I havn't and they can exist for hours. Even after additional protection from spam robots will be added to the forum, there will be some probability of spam messages anyway, and group of moderators can handle such cases very quickly (especially if there is 2-3 people in this group or more).
