Errata

Screenshot doesn't match code. It says (using layout) is should say (using hello layout)

In the label_for method, defined as:
def label_for(method, options={})
label(options.delete(:label) || method).safe_concat("<br />")
end
If a :label is defined, the label's for property will be formed using the :label value rather than the method. For example, using the call <%= text_field :name, :label => "Your name" %> produces the following HTML:
<div class='field required'><label for="person_Your name">Your name</label><br /><input id="person_name" name="person[name]" required="required" size="30" type="text" /></div>
In the above, the for property is "person_Your name" instead of the field's id, "person_name"
Changing to:
def label_for(method, options={})
label(method, options.delete(:label) || nil).safe_concat("<br />")
end
corrects the error, yeilding the following HTML:
<div class='field required'><label for="person_name">Your name</label><br /><input id="person_name" name="person[name]" required="required" size="30" type="text" /></div>