It did not happen in our 5 session playtest. (But, I must admit, it has never been a problem in our games at all for many reasons, including of course, players that do not play that way).
Reasons that may contrinute to it not happening in our game:
1. Random Encs: Not totally random - I have a chart for each 'region/realm' (in fact I have a system for determining and organising realms from tribes to empires). So, creatures from an area 'may' come along anyway.
2. Players roll the Random Encounters!: Like [MENTION=12377]77IM[/MENTION] above I try to keep it impartial. I don't just keep throwing random encounters at the party, but they know there is always a chance. (Again - my realms sheets inc how 'Dangerous' an area is which modifies chance of encounters [an expansion on the Pathfinder concept of 'Comunity Modifiers']).
3. Cumulative Random Encounters: Getting involved in a fight or doing something obvious like lighting a large fire or making lots of noise automatically means an extra random encounter is rolled. So one encounter can surely lead to another.
4. Other NPCs and plots may still go on. Kind of a time limit thing. For eg if prisoners are being held, I might rule each night there is a 50% one is killed and eaten, so if the PCs delay too long then they will have less to save (and the survivors may let them know about it). In any case the enemy go on acting as normal.
5. Enemies encountered act: If PCs back off after fighting a group without finishing it, well, that group will likely 'do something'. Again, I am likely to write a few options and roll randomly or use the good ol' "#1 Rule of Dungeoncraft" and give a 50% chance the attacked enemy will do each idea. So, say the PCs 1/2 finished the hobgoblins I might roll 50% for each of the following (so more than one may occur) OR just choose one:
A) Hobgoblins double their watch
B) Hobs send out a search/hunting party for the PCs
C) Hobs fortify their position and prepare for PCs return
D) Hobs pack up and leave (perhaps leaving signs, like dead prisoners that that have gone)
E) Hobs seek alliance with another tribe
F) Hobs seek out PCs for truce or simply cast captives out so there is no reason for PCs to bother them.
Those are a few egs off the top of my head, but the point is that the 'enemy' and 'setting' go on around the PCs no matter their choices. The world and everything in it doesn't rest and if they have already been encountered, then they do 'do something'.
Note also, that for our
Caves of Chaos playtest, 'town' was a few days away. They went back once to return freed prisoners and ended up buying more gear and recruiting more people. There was a ruined keep 6 hours away, though one night PCs simply hid in the woods (after setting up a diversion - making it look like they went the other way (along a river)). So, yes, when they do rest, my players are thinking of who may be after them if they have stirred the nest
I prefer not to use metagaming to encourage my players (but can't recall having to do so), though for a playtest I might consider it.