We do our best to ban spambots as soon as we see them. User reports can be a great help in that, especially when they move to profile posts as opposed to creating new threads.
Not news at all, this happens at night specifically when no staff are online. Once it gets past a certain time the "New Profile Post" section is filled to the brim with bots. This has been happening for quite a long time if I can recall. I just never bother mentioning anything about it because at some point either in the night or in the morning it gets resolved.
Maybe filters could be tightened. XenForo has great anti-spam measures. XenForo Community, for example, rarely sees spam attacks. Can't get rid of all of it, but it can be significantly reduced.
Oh thank goodness. Here I thought I was doing basically nothing by reporting bots. I'm subscribed to the New Arrivals board, so I get an alert for each new thread, and I'd suggest the same to whoever wants to make the mods and admins jobs easier.