No arguments from me about the incorrectness of this. In a recent game I was taking it for granted that my greatsword wielder was getting his 1.5x strength bonus when using a buckler. But it dawned on me at some point that he should be doing more damage, so I started checking, and sure enough, with 18 strength only +4 was being added to weapon damage. I unequip the buckler and the str bonus immediately bumps up to +6. That character took that buckler and cleaved it in two at that point.
That bites. I had my cleric craft a masterwork buckler up to +3 because I figured four points of armor were a fair trade for a minus one to hit. If I am also losing two points of damage bonus for strength while weilding a two-handed weapon it brings the equation back to not worth it again.
If you have an archer or x-bowman, it will work without a malus. However someone's reported that it only computes when you're not attacking anyway...
In my games, I have noted that you do still get the magical bonus of the buckler with a two-handed melee weapon (not sure what the rules interpretation should be) -- so effectively you can get +3 for giving up the -1 to hit (assuming buckler +3). I never noticed that I wasn't getting 1.5 * STR bonus (as Marceror reported earlier in the thread).
As far as using a bow with a buckler equipped, as far as I can tell there is absolutely no negative to calculated. I can equip and unequip the buckler and my attack bonus displayed in the interface does not change. I haven't tried this with an X-bow, however, so I don't know the answer to this.
Right, there's no penalty for using a buckler with a bow or crossbow. However, it has been stated that ToEE (correctly) removes the AC bonus of the buckler in any round you attack. That's what he's trying to say.