It depends on the pattern of the requests. If they're requesting different URLs each time, for example, then it could go under the radar for a period of time. If it's a resource where normally someone would not request more than ~15 articles in an hour (like what it might be for PACER), you can have alerting for when more than 50 articles are accessed in an hour.

Generally speaking rate limiting to that degree will help you evade detection though.

That really depends on the system, its provisioning, and how typical traffic patterns correspond to storage.

Some systems respond far better to random queries, hitting data in different places, often on separate spindles or storage devices.

Others prefer sequential requests, avoiding random seeks across heads.

And there are systems whose performance degrades spectacularly even under light load.