Even to allow tori to continue with a wrongly executed technique might be dangerous. In that situation be even more aware of your control (Budo!). It is often in these situations where 'accidents' happen....
@Don, agreed. totally.
I stress this in class: the goal in Aikido is not about throwing or hurting someone. When you want to hurt someone go out and practise aikijujutsu or some other external martial art.
It is tempting when aite taps out 'early' to simply continue the hold to make your point that you think his/her limit has not yet been reached. But is is soo wrong! It is a reflection of your mindset when this happens.
I think it holds true in any martial art. If I was in bjj class and my fellow students or coach decided I was tapping out too soon my a shoulder attack or a choke and held it longer I'd be just as angry (probably even more so due to the nature of the training). Respect and gratitude to your partner for allowing you to work with them is a must in any martial art. It's the only way we can both grow together. (And the only way you can keep students and training partners)