I think I understand; tiels are basically really sweet in nature and may not understand if they are being... overly sweet to another bird like that. Simo thus far seems to have a really sweet nature himself and has at least so far never shown any aggression; weather this is how ringnecks generally are I don't know. His beak is indeed powerful, he's made short work of nut shells (he LOVES to break the shell of the nut, but doesn't bother to eat what's inside). He's only ever bitten me once, and even that was extremely early in his life, when he had just moved into our house and I was dumb enough to transfer him to his new cage by grabbing him. (aaargh, looking back at this I feel so annoyed - after a stressful trip some big scary stranger grabs you, what was I thinking?). But that's the only time so far - even when he decided to explore my hand himself he nibbled on my fingers and knuckles very very gently. Still, I've a lot to think about now. One of us is always home to keep an eye out on him and his future buddy in any case!
There do seem to be quite a few videos out there or IRNs with other species of birds but I know better than to trust youtube on subjects like this!
I don't -have- to get a tiel per se, but the idea was to adopt a bird instead of buying. Lots of people take budgies and tiels and don't understand what birds really need and give them up for adoption!