This is a Rails 3 application with HAML.
I have the following:

```
= f.fields_for :bar_memberships do |bar_membership_fields|
  = 'FIELD'

```

I have encapsulated the problem. This code prints:
FIELD 
FIELD
FIELD
as expected.

But the following code:

```
= f.fields_for :bar_memberships do |bar_membership_fields|
  - if bar_membership_fields.object.new_record?
    = 'FIELD'

```

Renders a lot of HTML-escaped hidden inputs in the source code, and displays them on the page!

```
'<input id="person_bar_memberships_attributes_0_id" name="person[bar_memberships_attributes][0][id]" type="hidden" value="824" />
<input id="person_bar_memberships_attributes_1_id" name="person[bar_memberships_attributes][1][id]" type="hidden" value="825" />'
FIELD

```

Any idea?