No, because it requires an &Vec<_> and that doesn't implement Default and for good reason. Just ask yourself, where would the default empty vec live so that you could create a reference to it.
When using unwrap_or(&vec![]), it lives in the enclosing stack. Without the reference, you could use unwrap_or_default().
Thanks for your reply that cleared it up. Was a bit confused why the `unwrap_or(&vec![])` worked but as you said it lives in the enclosing stack.