Couldn't agree more. Any set of talented developers in an open environment will naturally pair when one or the other has a critical piece of code to write or some code they want input on. The key is getting the right sort of developers who know when they are stuck, and a no-blame environment where you can be called on bad code decisions.
Trying to mandate this sort of sharing through policies strikes me as ridiculous and the sort of thing that drives good developers out. Training a junior is one thing, having them assigned to 'help' is something entirely different.
I've always thought of pair programming as something that consultancy firms dreamed up to charge clients twice as much for the same amount of work. Perhaps I'm just cynical and tainted as it was a highly-paid consultancy firm that first tried to sell me on the idea.
