As is so often the case, the players went off on a plot direction I wasn't intending them to hit-- leastwise, not this early in the game. As a result, they've started to pillage an abandoned temple I wasn't expecting them to get to for several additional levels. The problem is that there is an item that they'll eventually need to acquire for some in this temple, but it's way out of there league right now-- I was expecting them to approach this around level 15 or so, and they're level 4 at the moment. For once, I've got a party that actually uses teamwork and works well together, so they did a fairly good job of getting past most of the encounters without too much difficulty on their part. The temple vault was a series of increasing difficulty level traps/locks/monsters, and I wrongly assumed that the PCs would back off and come back to it when they were stronger when they reached something they couldn't get past easily. They kept on past the traps that the rogues in the party couldn't disable; they kept on past the door that they couldn't unlock, bashing it down instead; they kept on past the monsters that were significantly higher in challenge rating than they-- and through some very clever use of the prior traps and nature of the passageways to deal with monsters. They've now reached the crypt at the end of this series of encounters, and we called it a night there.
I'm torn at this point. On the one hand, I'm very tempted to let them suffer the negative consequences of their actions, as, depending on who opens the sarcophagas and takes the item in question, it could wreak serious havoc on the party. I'm somewhat annoyed at the fact that they wouldn't take the hint and turn back when things got much harder than they should have been. But at the same time, they were doing an exceptional job of working as a team-- far better than I've ever seen them do-- and of thinking their way past these obstacles. So I think they deserve to be rewarded as well. But if they manage to successfully acquire the item in question, they have no idea what it does, and, due to its nature, they'd have a very difficult time finding someone who did, so they'd have to sit on it until they were close to the level they should have acquired it at in the first place. I'm still deciding what sort of consequences to dish out, but I'm wondering what y'all do when you've got players that bull ahead on things when it should be fairly clear that they should turn back.
Incidentally, in cases like this, if the characters get killed, I have no sympathy, and let them die-- however, they played it very well, and though I got the fighter down to 1 HP at one point, that was the closest I can to killing a PC.