AbdulAlhazred
Legend
Well, I'm not saying it would or wouldn't be fun or better or worse. FOR YOU, with your agenda, you might find it more fun, but I wonder if this is really true. I mean if you say decided that you would eat lunch and buy a couple healing potions before setting out, gambling that this would benefit you more than arriving early might, and then you arrive and the DM says "Sorry, all you find is a deserted temple and a bloody altar, the action finished up an hour ago!" you might start to feel differently. Maybe you (and certainly the DM) would be wishing that he'd decreed that getting lunch took 5 minutes instead of 25 minutes, or that you didn't have to haggle for 15 minutes to get the potions you needed. You see where I'm coming from? IME, lots of it, almost every DM out there will succumb to that logic.Why would the DM contrive such a thing? Why would the DM want to contrive such a thing? Why would it be "fun" for the PCs to encounter such a contrived scenario?
Now, ALTERNATELY, the DM could cast the whole adventure in terms of the struggle to arrive at the temple within the allotted time frame. 4e handles this perfectly, you create a skill challenge, the results of which determines when the PCs arrive. If they succeed they arrive in the nick of time, if they fail they're too late. Maybe they get a choice to take an extra failure right off if they want to get some potions or lunch first (or maybe they just have to make a hard choice, but note that integrating it as a cost in the SC makes it explicit without requiring DM judgment calls on the absolute time). The result is BETTER than it would be in AD&D, where it all must rest entirely on the DM fiat of time which is putting pressure on the DM to undermine the game's agenda. The SC isn't even undermining a simulationist agenda, it is just creating transparency which makes things more interesting.
Another thing that using an SC does is it focuses the DM's mind on the plot issue at hand, what happens if the PCs don't arrive in time? Given that this is now an explicit outcome of a game process it is more likely to be addressed explicitly as well (just speaking from experience with 4e myself here, and having run things in a more 'classical' fashion in my 2e days by contrast). The drama is also moved more towards things that the players have a hand in, as opposed to largely controlled by the agenda of the evil bad guy and his ritual schedule.
That's kind of what I was getting at, while I was rambling. You could frame lunch as a Skill Challenge where you negotiate through the market, diplomacize your way through the line, and stuff your face with the goal of spending as little time as possible on the task. The time spent depends on how well you do on the Skill Challenge. (And conceivably, since it matters, it's worth XP and someone could gain a level from this.)
Or the DM could describe the relative busy-ness of various market stalls, and the different foods available, so that the time required is a reflection of the circumstances and player choice rather than the result of some number of skill checks. The fastest option is always to just eat trail rations, but how often are you going to have access to fresh food at the market? and do you really want to miss out on this while you're here? Granted, it's all through the lens of what the DM thinks is reasonable, but that's true of everything in D&D, and the DM is a neutral arbiter in all things.
I haven't seen too many truly neutral DMs. DMs have agendas just like players do, and I'd always rather see SC mechanics and other transparent 4e techniques used to keep things going on the straight than often biased DM calls. This just comes back to the very start of this whole long conversation several days ago. 4e provides transparent resolution mechanics that empower the players because they make things more explicit.