I think no touch throws are possible, but only if either;
i. your uke is conditioned to react in a certain way to an approaching fist/strike
ii. you can judge uke's response well enough to achieve it.
Ueshiba can be seen to do some 'no-touch' throws. But similarly when you look at him, some ukes are obvioulsy throwing themselves whilst others are not. If you are going to blend with someone, you have to blend with what they do, so if they are throwing themselves that's their stupidity.
I think no touch throws are possible - but only if you are prepared to follow through if the uke does not do the expected reaction. One way to test it is to do it on a complete beginner - this helps you to differentiate between a real response and uke conditioning.
I answered no to the poll, just because most sensei's I have seen do 'no touch' throws, are relying on a conditioned response of uke, which I think cannot be depended upon for people outside the dojo.