It seems like those networks will simply have to modify that heuristic. Given that a bot maker could easily emulate mIRC's delay regardless of what mIRC does or does not do (and this server check is now documented on the official forums for all to see), I really don't see how effective or "reliable" such a check really is, but I guess I don't have the data to look at.
As Khaled pointed out, the internal hardcoded limit is no longer necessary thanks to improved flood control handling. Since the feature was primarily meant to users don't get flooded off an IRC server and not so it would bypass a bot-check, this change makes the interface more consistent.
