I'm not Aikikai, but I definitely don't cause pain in any technique.
1. It doesn't always work, and just pisses most people off.
2. It gives uke too much information about what I'm doing.
3. If I can get uke to lock himself up, why would I need/want to hurt him?
You "don't cause pain in any technique"? Really? I find that very hard to believe. Being immobilized against your will sometimes hurts. What you've listed are good reasons not to make pain the goal of technique and not to trust pain to make technique work, but good technique still hurts sometimes.
Any technique can theoretically be applied without pain, but no one is so good that he makes his techniques work 100% of the time against every uke without causing any pain. I can say from personal experience that even Ikeda, Tasaka, and Moriyama aren't that good, and in light of that, I feel pretty confident saying that no one is.