If your, Meh not undocking now, the addition of POS isn't going to motivate you to undock. If POS is intiated where it is continually vulnerable, that is it must be defended 24/7/365, corporations are going to need a very large ACTIVE player base.
** Insert comment about how they have something like this in Eve and it works there so it will work in this game, insert insert reply about this isn't Eve and/or the player base is 1000 times smaller; generally just comment on how it will work here instead of how it works somewhere else **
The most likely scenerio is that 8 to 10 attackers show up against your 2-3 defenders. And the first time it happens, you undock and lose the POS, and after that you don't bother unless odds are even or better.
Now depending on what the POS does and how expensive it is, an even more likely event is that alliances and corporations just don't build them; or they build and lose the first one and don't make another.
If this happens, that is if the POS system is added to the game and fails, that will probably be the last straw.
The good news, is that POS isn't promised any time soon, so that gives them time to get it right. We also don't have really any indication about what and how POS is going to be implemented, so its all speculation.
What I would like to see for functional POS items, like remote mining outposts, is that they are fully sheilded and basically tank all but a full scale assault, but also are not functional. To start producing, the sheild must be dropped.
This prevents small or even medium sized groups from destroying expensive POS's during corporate 'off hours', but doesn't make it invincable. But the POS provides no benefit unless it is vulnerable. If however an alliance takes over an area, they can send 50+ bots over and clear off the offending object.
Things like stations wouldn't neccesarily be sheilded, but have so much HP that it would take hours for a large gang to kill it. And it would not be usable until the owner paid to fix the majority of the damage.