getting spoiled birds back...

Question
Hello,
I am a student, studying overseas and my two Cockatiels are staying with a couple, who unfortunately have been spoiling them like crazy because they really do love them. However, I fear that when I return from my studies, these two birds will need some serious retraining. They are in one cage at the moment, and both in good health. I do have another cage, so I could separated  them if this would be necessary. I will be living alone with them as well, so I will be the only person they will come into contact with for a while. My question is, how should I start retraining them when I get them back?

Thank you for your help!

Answer
-- What do you mean by "spoiling" and why is this a bad thing?   Since birds are our prisoners (not with us and out of the freedom of the sky by choice) isn't it our obligation to make their lives as much about them as possible?

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I'm not sure how anyone can spoil a bird?  Never once in my 35 years of doing this professionally have I heard that word ("spoiled") used in a negative way