I think ircd developers should add a throttled numeric, which includes the number of seconds the client should wait to reconnect (as it is mirc simply looks for "throttled" in the ERROR message) - the added 'penalties' for breaching the throttle are often far, far higher than 30 seconds.
There's no real way for mIRC to know how long it should wait, maybe each connect fail with "throttled" it should wait a little longer.
