It's not a prison even if you do use it. The defining characteristic of a prison is that you cannot leave it. I can stop using an iPad any time I wish. And y

It's not a prison even if you do use it. The defining characteristic of a prison is that you cannot leave it. I can stop using an iPad any time I wish. And yes, important data should not be locked in non-portable formats. At the same time, I've never found myself in a situation where I simply could not extract important data from a non-portable format into a more portable one.