Edge Case: Stand Still and Reach

[Warchon]

So, I've come across an interesting ruling that creates a question, and I'm just curious what people's POV on this is.

Apparently the 5-10 rule for counting diagonals comes into play with reach weapons. That much seems reasonable--your 10 foot reach doesn't allow you to attack two diagonal squares away.

This does however create a situation where coming in at a full diagonal means you can move at full speed and get adjacent to a reach weapon user without provoking. Now, I'm sure any DM will laugh and just say by RAI you'll get your AoO, as long as he's closing in on you and not just coincidentally passing through that non threatened square.

The strangeness comes with the Stand Still feat, which allows you to forego your normal AoO for leaving threatened status
squares and (potentially) end the opponent's move instead.

So do you defeat the purpose of the feat, allowing the enemy to close in? Trap him in a square in which neither combatant can actually hit the other? Or just kind of fudge an "in between squares" position where your Reacher can hit but the melee guy cannot?

[Goaty14]

No, having 10 ft reach still means you threaten in squares adjacent to you. You threaten squares adjacent to you with 5 ft reach. The purpose of Stand Still is to keep enemies from running away -- no AoO is granted for entering a threatened square.

[Warchon]

The vast majority of reach weapons explicitly do NOT threaten adjacent squares or allow you to attack them. Enemies leaving the threatened "outer ring" to get up close and personal where you are more vulnerable is what provokes in this case. (Or, yes, moving within or leaving said ring, but those cars are irrelevant to the question)

[Gnaeus]

This is not correct. 3.5 rules that you do threaten the 15’ corners with reach weapons. I think it’s DMG 29 and 308, PHB 136.
http://www.d20srd.org/srd/combat/attacksOfOpportunity.htm#reachWeapons
Here’s the SRD quote. See the note under reach weapons

PF lacked this language, causing rules debate on this issue, which was resolved when it was clarified that it works the same way.

[Warchon]

To clarify, I'm talking about the use of reach weapons, not being a monster with a natural reach. Though frankly threatening adjacent squares doesn't prevent the conundrum I outlined above--an enemy could still run in diagonally, passing through your non threatened diagonal square and get adjacent without provoking, by a strict reading of the RAW

[Warchon]

This is not correct. 3.5 rules that you do threaten the 15’ corners with reach weapons. I think it’s DMG 29 and 308, PHB 136.
http://www.d20srd.org/srd/combat/attacksOfOpportunity.htm#reachWeapons
Here’s the SRD quote. See the note under reach weapons

PF lacked this language, causing rules debate on this issue, which was resolved when it was clarified that it works the same way.

Ah, yeah, that does put it up in black and white then. Thanks!