I'd echo that one: remember how important surprise is. The effective level of an encounter goes up or down dramatically based on whether or not the party is awake and alert to the upcoming encounter, or is half asleep, out of armor, and the person standing watch missed his Spot check.
Flip side, most wilderness creatures will break and run when faced with significant opposition; anything which has really startled or injured them suffices. You don't have to play them as fighting 'to the death'. Likewise, there are plenty of creatures which, if they 'get the drop' on the party, will take one look and decide to go elsewhere for a meal which is less well defended.
I'd definitely say 'roll the spot and listen checks yourself'; also, remember that rolling an encounter on your 'random encounter chart' doesn't have to mean 'you are now within 20 yards of the creature', it could signify the point at which 'the party is now in range of some clues about the creature'. E.g., if your roll specifies a nocturnal creature during the day, let the party have neared its lair, with chances of detecting its tracks or spoor, and chances of waking it up by being too noisy, etc.
