Also, my mom's 'toos do end up at birdsitters for a couple of weeks when she had to go to Germany. They don't quite have the same schedule, don't have the same amount of time out, but they do fairly well. They do come out though (some places don't really allow this, sadly).
She's got them used to being in for longer periods of times because of situation like these; while she could let them out all day, she's fully aware that not everyone could and therefor has them in during the day just in case she does have to leave for longer periods of time or if she does need to re-home them (they will most likely outlive her). And when she knows she's about to leave, she does slowly extend the time in the cage a couple of weeks before her departure so they can ease into it.
It's all about getting used to it gradually, which can also apply to Pois.
I do think Pois are more adaptable than 'toos but they still need to be eased into transition.