It looks like http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#526 addressed this problem (or something very similar to it) as a potential defect in the standard:
1) Parameters taken by const reference can be changed during execution of the function
Examples:
Given std::vector v:
v.insert(v.begin(), v[2]);
v[2] can be changed by moving elements of vector
The proposed resolution was that this was not a defect:
vector::insert(iter, value) is required to work because the standard doesn't give permission for it not to work.