One VS2010 bug ? Allowing binding non-const reference to rvalue WITHOUT EVEN a warning?

That is a known issue/feature of the VS compilers. They have always allowed that and there does not seem to be any push into removing that extension.

The compiler will issue an error with Disable Language Extensions turned on, and a warning at /W4. However, removing this code will break previously compiling code, and Microsoft is very reluctant to do that. This is also why they won't fix their SFINAE support.