Property never null c#

When refactoring code, I come up with instances like the following

private string _property = string.Empty;
public string Property
{
    set { _property = value ?? string.Empty); }
}

Later on in a method I see the following:

if (_property != null)
{
    //...
}

Assuming that _property is only set by the setter of Property, is this code redundant?

I.e is there any way, through reflection wizardry or other methods that _property can ever be null?