Not every change needs map refreshing. Containers and some other things do not. In Ancient Times, during the second closed test of the so called 'faction mod' we used to nag Scypior to add some lockers to our base and sometimes he did that, simply by creating a locker in his inventory and putting it on the ground. Once he even put a Gizmo's dead body (along with his desk) in my house, but it was possible propably because this was a critter.
(oh, those were the days...
)
Generally I find this Idea a little far-fetched, but some simpler additions could be possible.
In example, instead of making a tent (which should still be possible) a player could use a cartain encounter map with some kind of notice board and a box/locker. By using the notice board he would declare this site as his own (as with tents you could have only one such place and making a tent would make it disappear) Such sites would be rather rare and generally one would have to put a lot of effort to find one. Examples of such 'alternative tents' could be:
In a city ruins area: a desolated basement of a house.
In a mountains area: a small cave (the smallest one)
In desert area: some abandoned shack
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About notice boards or sth like that: I think such thing could work as a simplified base computer -
the owner could add and remove people sharing the tent with him (then a char could have only one tent/home. Building another one would automatically remove a char from the previous and allowing to be added to sb's tent would mean saying goodbye to your own tent)
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As to creating lockers - I think the game engine allows to make a container. Such container could be put on the ground or removed by using the science skill or a crowbar on it. They also could be installed only in tents/bases.
This is generally only a loose idea, I have no will to fight for it with a band of naggers ;]
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One additional offtopic note: If we could collect all the new, reasonable crafting items proposed to be implemented(lockers, radio headsets, motion scanners, radiation counters, robots) there would be a call for another profession - engineer?