I've done this a few times, and there's a couple of caveats here.
The first being is that heat can still be calculated I assume, but it matters little because once you leave the area at enough distance all spawning seems to stop.
But, if you wish to leave you should definitely get rid of any local pest zeds that might cause you some damage. This is tested in both crafting bases, dew
collector fields, and horde bases that generate heat.
I do not know how much specific distance you need before this happens. I've left an area and come back and found things dead, but this has been mostly
when the sun comes up. Remains and bags left behind, but not in any huge quantity. I've also had people wander close enough to a dew collector field,
which then a quick spawn in that someone could easily miss could do some damage once you've continued past.
In multiplayer, our collector fields can be fully loaded (up to 30 some times), often on top of cobble foundations that are typically 3 blocks high.
I'll surround those structures with wood traps, and a raised staircase that ends in a jump to reach the top of the structure. I've yet to see a single zed get on top
and do any damage, but I have definitely seen evidence of trap destruction and cracks in the foundations. We set them up away from any other structure
we build up. if one side of that structure faces really close to a trader, then no spawns at all will happen on that side.
