Hey Will,
With an issue like that, it really depends on the plan that the customer has. By default, we don't limit a customers connection pool entries unless they have a "rogue" module that is eating connections and causing problems for other users and when we do that, we do fully inform the customer that we've capped their connections and we give them SQL traces so that they can get a patch from their module vendor - the only reason that we cap them at all is because SQL does have a limit on how many concurrent connections it can service.
In a case like your customer, what we'd want is for them to give us a heads up ahead of time that way we can make sure that the service level they are on matches what they are going to need for their burst. For example, one customer of ours was a finalist in a major American singing competion. When they started out with us, they were on our professional $50/mo shared hosting plan which was fine for them, but each week we took a look at the traffic and CPU utilization that they had and we analized if it was going to be enough for their spike the following week during TV votes. When Finalie night came around, they were doing 300-500gig of traffic per hour and their hosting didn't even flinch, but that is because we had a working relationship with them and were able to set up a multi-server environment to match that spike. Since they're no longer on TV any more, we've decommissioned most of their equipment and now they're back to a single server config.
To answer your question about optimizations, there is an option on our signup form that let's people opt-in or opt-out of our 150+ point performance optimization service. I can't disclose exactly what it does, but it basically does some very heavy optimizations on your SQL database and other parts of the site. The optimization also happens on a nightly basis as well (we're performance nazi's over here. :) ) so we always like our customers to have the best performance possible. Also, if you're on our Pro plan or higher, we also throw in a free KeepAlive service on your site so you never get hit with that first-load time.
Whew! I think you worked me up into a full blown sales pitch. :) Anyway, if you have any questions, I'd love to talk with you about your needs. My number is 402-650-6072.