This depends on the throughput of spamming that's going on. The throughput can be quite large if there's a significant amount of people cooperating. Also, this

This depends on the throughput of spamming that's going on. The throughput can be quite large if there's a significant amount of people cooperating. Also, this means that admins have to spend a nontrivial amount of time on such work on every single day. The examples I know of are groups of political movements that have a lot of haters, so that might be somewhat of an edge case.