Artoomis said:
In both cases it's clear that the tables are NOT all-encomposing and one should draw one's own conclusion about activities not listed.
In other words, it's a DM judgement call for activities not listed. It is not a proper reading of the RAW to treat these lists as all-encomposing such that something not listed cannot provoke an AoO.
Ok. Let's say it is a judgement call.
Many of the AoO rules listed so far in this thread discuss attacking a creature who can defend himself. Only that defending creature gets to AoO, so none of these rules (e.g. grapple, disarm) are applicable to
any other nearby creatures if performed against a helpless creature.
A few of the AoO rules listed so far in this thread discuss attacking or manipulating an item. Not a creature, but you could extrapolate the same action for an object to a helpless creature considering that it seems reasonable that you would have to "perform a distracting action" regardless.
Of these, we have:
1) Pick up an item: yes
2) Open/Close a door: no
3) Sundering a non-held/non-worn item: no
Which of these is closest to touching a helpless creature?
Well, picking up is not just touching so much as it is grabbing and doing further manipulation on the object (including holding it).
Open/Close is fairly close to touching an item. It requires some minor effort to open/close, but not much. It is the closest of these three to just touching.
Sundering is not very close. But, it does illustrate that you can reach into an opponent's square without causing an AoO.
Touching appears to be a pretty simple action. In fact, Cast Move Touch implies that touching with a non-attack spell is practically a free action and there are no free actions in the table listed as provoking an AoO (in reality, the touch is part of the casting, but it does not provoke for casting, only the actual casting does that).
The argument that you have to lean down to do this is relatively weak as well. There are no examples of just leaning down provokes. In fact, falling to the ground does not provoke, so why would leaning to the ground provoke?
What are the anti-AoO supporters left with?
1) Non-attack touch is for all intents and purposes a free action as part of the casting and no free actions listed provoke.
2) Open/Close a door does not provoke.
3) Falling to the ground does not provoke.
What are the pro-AoO supporters left with?
1) Pick up an item provokes.
It seems that the pro-AoO supporters have very few rules that are very similar and even pick up an item is not very similar (grab and hold versus touch).
Note: Pick up an item is also a move action. Touching with a touch spell is not a move action. It is a free action as part of the casting ("You can touch as many willing targets as you can reach as part of the casting, but all targets of the spell must be touched in the same round that you finish casting the spell.").
Note: Even pick up an item does not apply to the leaning down argument since you could be picking up an object off of a table.
So yes, you could rule pro-AoO. But, you do not have many similar rules supporting that position, including "reach in" arguments for Grapple or Disarm or Overrun or Sunder which do not provoke for other nearby creatures.