Ohhhh the search progress bars. Didn't think of that. Will be fixed before release, but probably not for the next version.

The ban time isn't a specific length of time, but rather is based on the amount of requests from the host. We allow any request in the first 30 seconds we see that host, and then from then on we allow 1 request per 5 seconds. If they exceed that limit and continue to hammer, the amount of time they have to wait just grows and grows.

(And yes, client side queueing is needed, but will not be in 4.0.)