Upvoted for witty reply.

I didn't consider the moral implications. They are complex.

If you think about it though, the great future promise of the Singularity for humans is some type of uploading into designed virtual universes (the heaven scenario).

And in our current (admittedly) simple precursors, we have no compunctions creating sim worlds entirely for our amusement. At some point that would have to change.

I imagine there will probably be much simpler techniques for making safe-enough AI without going to the trouble of making an entire isolated sim world.

However, ultimately making big sim worlds will be one of our main aims, so isolated sims are more relevant for that reason - not because they are the quickest route to safe AI.

Especially since when we are talking about "Friendly AI" humans are not even remotely friendly in the relevant sense

Point taken - Friendliness for an AI is a much higher standard than even idealized human morality. Fine. But to get to that Friendliness, you need to define CEV in the first place, so improving humans and evolving them forward is a route towards that.

But again I didn't mean to imply we need to create perfect human-sims. Not even close. This is an additional measure.

I more or less assume that the AI will find a way to convince the creators to release it into the 'real world'.

This is an unreasonable leap of faith if the AI doesn't even believe that there are 'creators' in the first place.

Do you believe there are creators?