Edit: And, to be clear, my claim was that players have major incentives (in every edition, not just old-school ones) to investigate before they act. That investigation will, in part, be an effort to learn whether it is worth their time to do something. It may be that they really, really want whatever is in a particular place, but if they know it's full of monstrously powerful undead and an ancient black dragon, they're not going to go there until they are prepared, by whatever means (gaining levels, finding/buying gear, recruiting allies, whatever.) Likewise, a place that has just a mere kobold warren is unlikely to be of interest to someone who can slay dragons; that doesn't mean they have no interest at all in the place, but time and resources are finite. If the kobold warren is a concern, as others have said, buy them off or pay people to clear it up (and thus the cycle of adventuring turns!)